Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D401/00—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom
  • C07D401/14—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom containing three or more hetero rings
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P3/00—Drugs for disorders of the metabolism
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P3/00—Drugs for disorders of the metabolism
  • A61P3/08—Drugs for disorders of the metabolism for glucose homeostasis
  • A61P3/10—Drugs for disorders of the metabolism for glucose homeostasis for hyperglycaemia, e.g. antidiabetics
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P43/00—Drugs for specific purposes, not provided for in groups A61P1/00-A61P41/00
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D213/00—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
  • C07D213/02—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
  • C07D213/04—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
  • C07D213/60—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
  • C07D213/72—Nitrogen atoms
  • C07D213/75—Amino or imino radicals, acylated by carboxylic or carbonic acids, or by sulfur or nitrogen analogues thereof, e.g. carbamates
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D401/00—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom
  • C07D401/02—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom containing two hetero rings
  • C07D401/12—Heterocyclic compounds containing two or more hetero rings, having nitrogen atoms as the only ring hetero atoms, at least one ring being a six-membered ring with only one nitrogen atom containing two hetero rings linked by a chain containing hetero atoms as chain links
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D417/00—Heterocyclic compounds containing two or more hetero rings, at least one ring having nitrogen and sulfur atoms as the only ring hetero atoms, not provided for by group C07D415/00
  • C07D417/02—Heterocyclic compounds containing two or more hetero rings, at least one ring having nitrogen and sulfur atoms as the only ring hetero atoms, not provided for by group C07D415/00 containing two hetero rings
  • C07D417/12—Heterocyclic compounds containing two or more hetero rings, at least one ring having nitrogen and sulfur atoms as the only ring hetero atoms, not provided for by group C07D415/00 containing two hetero rings linked by a chain containing hetero atoms as chain links
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D417/00—Heterocyclic compounds containing two or more hetero rings, at least one ring having nitrogen and sulfur atoms as the only ring hetero atoms, not provided for by group C07D415/00
  • C07D417/14—Heterocyclic compounds containing two or more hetero rings, at least one ring having nitrogen and sulfur atoms as the only ring hetero atoms, not provided for by group C07D415/00 containing three or more hetero rings

Definitions

• the present invention relates to novel compounds, to pharmaceutical compositions comprising the compounds, to a process for making the compounds and to the use of the compounds in therapy. More particularly, it relates to certain glucokinase activators useful in the treatment of diseases and disorders that would benefit from activation of glucokinase.
• Glucokinase (hexokinase IV or D) is a glycolytic enzyme that plays an important role in blood sugar regulation related to the glucose utilization and metabolism in the liver and pancreatic beta cells. Serving as a glucose sensor, glucokinase controls plasma glucose levels. Glucokinase plays a dual role in reducing plasma glucose levels: glucose-mediated activation of the enzyme in hepatocytes facilitates hepatic glucose update and glycogen synthesis, while that in pancreatic beta cells ultimately induces insulin secretion. Both of these effects in turn reduce plasma glucose levels.
• glucokinase variants with decreased and increased activities are associated with diabetes of the young type (MODY2) and persistent hyperinsulinemic hypoglycemia of infancy (PHHI), respectively.
• MODY2 young type
• PHHI hyperinsulinemic hypoglycemia of infancy
• NIDDM non-insulin dependent diabetes mellitus
• overexpression of glucokinase in dietary or genetic animal models of diabetes either prevents, ameliorates, or reverses the progress of pathological symptoms in the disease. For these reasons, compounds that activate glucokinase have been sought by the pharmaceutical industry.
• WO 2007/117381 A2 which was earlier filed but published after the present application, also discloses glucokinase activators based on substituted pyridines.
• thiourea compounds 1-(5-chloro-3-phenoxypyridin-2-yl)thiourea, 1-(5-bromo-3-phenoxypyridin-2-yl)thiourea, 1-(5-bromo-3-(4-fluorophenoxy)pyridin-2-yl)thiourea, 1-(5-bromo-3-(phenylthio)pyridin-2-yl)thiourea, 1-(5-bromo-3-(4-cyanophenoxy)pyridin-2-yl)thiourea, and 1-(3-(2-bromo-4-fluorophenoxy)-5-(3-methoxyphenylthio)-pyridin-2-yl)thiourea;
• the 2-aminopyridine derivatives bearing at the 3-position an oxy-or thio-linked aromatic group and on the amino group a thiazolyl or 1,2,4-thiadiazolyl substituted by a polyhydroxyalkyl or polyhydroxycycloalkyl group at the 4 or 3 position of the thiazole or thiadiazole ring, respectively are glucokinase activators. Certain of these compounds have been found to have an outstanding combination of properties that especially adapts them for oral use with controlled plasma glucose levels. Such compounds may be synthesized by synthetic routes that include processes analogous to those well known in the chemical arts, particularly in light of the description contained herein.
• the starting materials are generally available from commercial sources such as Aldrich Chemicals (Milwaukee, WI) or are readily prepared using methods well known to those skilled in the art (e.g., prepared by methods generally described in Louis F. Fieser and Mary Fieser, Reagents for Organic Synthesis, v. 1-19, Wiley, N.Y. (1967-1999 ed .), or Beilsteins Handbuch der organischen Chemie, 4, Aufl. ed. Springer-Verlag, Berlin, including supplements ).
• Schemes A-S further below show general methods for preparing the said compounds by using novel key intermediates of the present invention.
• the present invention provides a novel key intermediate for preparing a compound of general Formula I described further below, wherein D 2 is CH in Formula I .
• the invention provides a compound of formula: where:
• the present invention provides a novel key intermediate for preparing a compound of general Formula I described further below.
• the invention provides a compound of formula: where:
• the present invention provides novel key intermediates for preparing a compound of general Formula I: or a salt thereof, wherein:
• Compounds of Formula I include compounds, including salts thereof, wherein:
• (1-6C)alkyl refers to a saturated linear or branched-chain monovalent hydrocarbon radical of one to six, one to three, or two to six carbon atoms, respectively.
• Examples include but are not limited to, methyl, ethyl, 1-propyl, 2-propyl, 1-butyl, 2-methyl-1-propyl, 2-butyl, 2-methyl-2-propyl, 2,2-dimethylpropyl, 1-pentyl, 2-pentyl, 3-pentyl, 2-methyl-2-butyl, 3-methyl-2-butyl, 3-methyl-1-butyl, 2-methyl-1-butyl, 1-hexyl, 2-hexyl, 3-hexyl, 2-methyl-2-pentyl, 3-methyl-2-pentyl, 4-methyl-2-pentyl, 3-methyl-3-pentyl, 2-methyl-3-pentyl, 2,3-dimethyl-2-butyl, and 3,3-dimethyl-2-butyl.
• R 13 is a polyhydroxy-(2-6C) alkyl.
• R 13 is a (2-6C)alkyl group substituted with two to three hydroxy groups, for example two hydroxy groups.
• Examples include ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, 1,2-dimethybutyl, 2,3-dimethylbutyl, tert-butyl, pentyl, neopentyl and isopentyl groups substituted with 2-3 hydroxy groups, for example 2 hydroxy groups.
• R 13 Particular values for R 13 include the structures:
• R 13 is a methoxy(polyhydroxy-(3-6C)alkyl). In certain embodiments, R 13 is a methoxy(dihydroxy(3-6C)alkyl).
• An example of a particular value for R 13 is the structure:
• the alpha carbon is in the S configuration. In other embodiments, the alpha carbon is in the R configuration.
• R 13 is selected from the structures:
• R 13 is 1,2-dihydroxyethyl.
• R 13 is a polyhydroxy-(2-6C) alkyl group in which one of the hydroxy groups is on the alpha carbon.
• the alpha carbon is in the S configuration. In other embodiments, the alpha carbon is in the R configuration.
• a particular value for R 13 is (S)-1,2-dihydroxyethyl or (R)-1,2-dihydroxyethyl, which can be represented, respectively, by the structures:
• R 13 is a polyhydroxy-(5-6C)cycloalkyl group.
• R 13 is cyclopentyl or cyclohexyl substituted with 2-3 hydroxyl groups, for example 2 hydroxyl groups.
• Particular values for R 13 include the structures:
• R 2 is Ar 1 .
• Ar 1 is optionally substituted with one or more groups independently selected from C 1 -C 6 alkyl, F, Br and CF 3 .
• R 2 when represented by Ar 1 include the structures:
• R 2 is hetAr 1 .
• hetAr 1 is unsubstituted. In another embodiment, hetAr 1 is substituted with one or more groups independently selected from (1-6C alkyl), Cl, CF 3 and (1-5C alkyl)OH.
• hetAr 1 is an optionally substituted 6-membered heteroaryl group having 1-2 ring nitrogen atoms.
• examples of hetAr 1 include unsubstituted or substituted pyridyl, pyrazinyl and pyridazinyl groups.
• the 6-membered hetAr 1 is unsubstituted or substituted with one or more groups independently selected from methyl, ethyl, isopropyl, chloro, CF 3 , CH 2 OH, and CH 2 CH 2 OH
• groups independently selected from methyl, ethyl, isopropyl, chloro, CF 3 , CH 2 OH, and CH 2 CH 2 OH
• Examples include pyridyl, methylpyridyl, dimethylpyridyl, ethylpyridyl, isopropylpyridyl, chloropyridyl, trifluoromethylpyridyl, hydroxymethylpyridyl, hydroxyethylpyridyl, methylpyrazinyl and methylpyridazinyl.
• hetAr 1 is an optionally substituted 5-membered heteroaryl group having 1-3 ring nitrogen atoms. Examples include pyrazolyl, imidazolyl and triazolyl groups.
• the 5-membered hetAr 1 is unsubstituted or substituted with one or more groups independently selected from (1-6C alkyl), CF 3 , Cl, or (1-3C alkyl)OH, for example one or more groups independently selected from methyl, ethyl, isopropyl, CF 3 , CH 2 OH and CH 2 CH 2 OH.
• Examples include pyrazolyl, methylpyrazolyl, dimethylpyrazolyl, imidazolyl, methylimidazolyl, dimethylimidzolyl, hydroxyethylpyrazolyl, and dimethylhydroxyethylpyrazolyl groups.
• hetAr 1 examples include ethylpyrazolyl and trimethylpyrazolyl groups.
• R 2 when represented by hetAr 1 include the structures:
• R 2 is a pyridyl or pyrazolyl ring substituted with one or more groups independently selected from (1-6C)alkyl.
• R 2 is pyrid-3-yl, pyrazol-4-yl or pyrazol-5-yl substituted with one or more groups independently selected from methyl and ethyl.
• Particular values for R 2 include the structures:
• R 2 is hetAr 2 wherein herAr 2 is a partially unsaturated 5,5, 5,6 or 6,6 bicyclic ring system having 1-2 ring nitrogen atoms and optionally having a ring oxygen atom.
• ring systems include 5,6,7,8-tetrahydroquinolinyl, 5,6,7,8-tetrahydroisoquinolinyl, 5,6,7,8-tetrahydroquinazolinyl, 6,7-dihydro-5H-cyclopenta[d]pyrimidinyl, 6,7-dihydro-5H-cyclopenta[b]pyridinyl, 6,7-dihydro-5H-cyclopenta[c]pyridinyl, 2,3-dihydrofuro[2,3-b]pyridinyl, 2,3-dihydrofuro[2,3-c]pyridinyl, 2,3-dihydrofuro[3,2-b]pyridinyl, 2,
• R 2 when represented by hetAr 2 include the structures:
• R 2 is hetAr 3 wherein herAr 3 is a 9-10 membered bicyclic heteroaryl ring having 1-3 ring nitrogen atoms.
• herAr 3 is a 9-10 membered bicyclic heteroaryl ring having 1-3 ring nitrogen atoms.
• ring systems include [1,2,4]triazolo[4,3-a]pyridinyl and [1,2,4]triazolo[1,5-a]pyridinyl rings.
• R 2 when represented by hetAr 3 include the structures:
• R 3 is SR 6 . Therefore, a particular embodiment of the intermediates of the present invention is represented by a compound of the above defined formula where R 3 is SR 6 ; and R 6 is Ar 2 , hetAr 4 , (1-6C alkyl), -(1-6C alkyl)OH, polyhydroxy(1-6C alkyl), - CH(R 9 )-Ar 3 , -CH(R 10 )-hetAr 5 , hetAr 6 , (5-6C)cycloalkyl substituted with 1 to 4 OH, (1-3 C alkoxy)(1-6C alkyl), or cyclopropyl(1-6C alkyl).
• R 3 is SR 6 and R 6 is Ar 2 .
• Ar 2 is unsubstituted.
• Ar 2 is substituted with one or two groups independently selected from Cl, (1-6C)alkyl, CN, CF 3 , and -O(C 1 -C 6 alkyl).
• Ar 2 is an optionally substituted phenyl.
• R 3 when represented by -S-Ar 2 include phenylthio, (chlorophenyl)thio, (fluorophenyl)thio, (methylphenyl)thio, (trifluromethylphenyl)thio, (dimethylphenyl)thio, (cyanotrifluoromethylphenyl)thio, (cyanophenyl)thio, and (methoxyphenyl)thio.
• R 3 when represented by -S-Ar 2 include the structures:
• R 3 is SR 6 wherein R 6 is hetAr 4 , and hetAr 4 is an optionally substituted 5-6 membered heteroaryl ring having 1-3 ring nitrogen atoms. Examples include optionally substituted pyridyl, pyrimidyl, pyrrolyl, imidazolyl and triazolyl rings.
• herAr 4 is substituted with one or more (1-6C) alkyl groups, for example one or more methyl groups.
• R 3 when represented by -S-hetAr 4 include the structures:
• An additional value of -S-hetAr 4 includes the structure:
• -S-hetAr 4 groups selected from -S-(methylpyridyl), -S-(dimethylpyridyl), -S-(methylimidazolyl), and -S-(methyltriazolyl).
• R 3 is SR 6 wherein R 6 is (1-6C alkyl)OH or polyhydroxy(1-6C alkyl).
• R 6 is (1-6C alkyl)OH or polyhydroxy(1-6C alkyl).
• polyhydroxy(1-6C alkyl) groups include 1-6C alkyl groups substituted with 2 to 3 hydroxy groups. Particular values include the structures:
• R 3 is SR 6 where R 6 is (5-6C)cycloalkyl substituted with 1-4 OH groups, for example 1-2 OH groups.
• R 3 is SR 6 wherein R 6 is CH(R 9 )-Ar 3 .
• R 9 is H.
• R 9 is (1-6C)alkyl, for example (1-3C alkyl), for example methyl.
• R 9 is CH 2 OH.
• Ar 3 is an unsubstituted phenyl.
• Ar 3 is phenyl which is substituted with one or more groups independently selected from F, Cl, Br, and (1-6C)alkyl.
• Particular values for R 3 when represented by S-CH(R 9 )-Ar 3 include the structures:
• R 3 is SR 6 wherein R 6 is CH(R 10 )-hetAr 5 .
• R 10 is H.
• R 10 is (1-6C)alkyl, for example (1-3C alkyl), for example methyl.
• R 10 is CH 2 OH.
• hetAr 5 is pyridyl. In other embodiments, hetAr 5 is pyrimidyl.
• R 3 when represented by S-CH(R 10 )-hetAr 5 include the structures:
• R 3 is SR 6 wherein R 6 is hetAr 6 and hetAr 6 is a 9-10 membered bicyclic heteroaromatic ring having 2-3 heteroatoms independently selected from N, S and O (provided the ring does not contain an O-O bond).
• Examples include 5,5, and 5,6 fused ring systems.
• Particular examples include thienopyridyl, thienopyrimidyl, isoxazolopyridyl, pyrazolopyrimidyl and imidazopyridine rings.
• herAr 6 is optionally substituted with one or two groups independently selected from Br, Cl, C 1 -C 6 alkyl, and O(1-6 alkyl). Particular substituents include Br, Cl, Me, and OMe.
• R 3 when represented by S-hetAr 6 include the structures:
• R 3 is SR 6 wherein R 6 is (1-6C)alkyl.
• R 6 is (1-6C)alkyl.
• a particular value for R 3 when represented by -S(1-6C alkyl) is SMe.
• R 3 is SR 6 wherein R 6 is (1-3C alkoxy)(1-6C alkyl).
• R 6 include methoxy(1-6C alkyl) groups.
• Particular values for SR 6 include -S(CH 2 CH 2 )OMe and - S(CH 2 CH 2 CH 2 )OMe.
• R 3 is SR 6 wherein R 6 is cyclopropyl(1-6C alkyl).
• a particular value for SR 6 is -SCH 2 (cyclopropyl).
• R 3 is SR 6 wherein R 6 is selected from (1-3C alkoxy)(1-6C alkyl), cyclopropyl(1-6 C alkyl), and pyridyl optionally substituted with one or more groups independently selected from (1-6C alkyl).
• R 3 is SR 6 wherein R 6 is selected from methoxy(2-3C alkyl), cyclopropylmethyl, or pyridyl-2-yl optionally substituted with (1-6C alkyl).
• R 6 of Formula I include the structures:
• R 3 is aryl. In a particular embodiment, R 3 is phenyl.
• R 3 is hetAr a . In certain embodiments, R 3 is pyridyl or pyrimidyl. In a particular embodiment, R 3 is 2-pyridyl.
• R 3 is Cl
• R 3 is Br.
• R 3 is CF 3 .
• R 3 is OR 6 .
• R 6 is an optionally substituted Ar 2 .
• R 6 is an optionally substituted hetAr 4 .
• hetAr 4 is a 6-membered heteroaryl having 1-2 ring nitrogens, for example pyridyl.
• R 6 groups include phenyl, chlorophenyl, pyridyl and methylpyridyl.
• Particular values of R 3 when represented by OR 6 include the structures:
• R 3 is OR 6 where R 6 is hetAr 4 .
• R 3 is OR 6 where R 6 is (1-6C alkyl).
• R 3 is OR 6 where R 6 is -(1-6C alkyl)OH.
• R 3 is OR 6 where R 6 is polyhydroxy(1-6C alkyl).
• R 3 is OR 6 where R 6 is -CH(R 9 )-Ar 3 .
• R 3 is OR 6 where R 6 is -CH(R 10 )-hetAr 5 .
• R 3 is OR 6 where R 6 is hetAr 6 .
• R 3 is OR 6 where R 6 is (5-6C)cycloalkyl substituted with 1-4 OH.
• the intermediates of the invention are for preparing a compound of Formula I , wherein D 2 is CH.
• the intermediates of the invention are for preparing a compound of Formula I , wherein D 2 is N.
• the intermediates of the invention are for preparing a compound of Formula I , wherein L is O.
• the intermediates of the invention are for preparing a compound of Formula I , wherein L is S.
• the compounds of Formula I being prepared with the intermediates of the invention also include compounds of Formula Ia
• R 2 is hetAr 1 .
• R 2 is hetAr 2 .
• R 2 is hetAr 3 .
• R 3 is Cl
• R 3 is Br.
• R 3 is CF 3 .
• R 3 is aryl
• R 3 is hetAr a .
• R 3 is SR 6 .
• R 3 is OR 6 .
• the compounds of Formula I being prepared with the intermediates of the invention also include compounds of Formula Ib
• compounds of Formula Ib have improved pharmacokinetic properties. For example, certain compounds of Formula Ib have been found to have increased oral bioavailability, increased exposure (i.e., increased blood levels over time), and/or lower clearance. In addition, certain compounds of Formula Ib have been found to have increased aqueous solubility.
• R 13 is (S)-1,2-dihydroxyethyl.
• R 13 is (R)-1,2-dihydroxyethyl.
• D 2 is N.
• D 2 is CH.
• R 2 is phenyl
• R 2 is pyridyl.
• the pyridyl group is substituted with one or more (1-6C)alkyl groups, for example one or more methyl groups, for example one methyl group.
• R 2 is selected from the structures:
• R 2 is pyrazolyl which is optionally substituted with one or more (1-6C)alkyl groups.
• R 2 is 1 H -pyrazolyl.
• R 2 is 1 H -pyrazol-4-yl.
• the pyrazolyl group is substituted with one or more (1-3C)alkyl groups, for example one or more methyl groups.
• R 2 is selected from the structures:
• R 6 is phenyl
• R 6 is pyridyl. In certain embodiments, R 6 is 3-pyridyl. In certain embodiments, the pyridyl is substituted with a (1-6C)alkyl group, for example a methyl group. Particular values for R 6 include pyrid-3-yl and 2-methylpyrid-3-yl.
• R 6 is (1-3C alkyl)OH. A particular value is - CH 2 CH 2 OH.
• Formula I being prepared with the intermediates of the invention also includes a compound of the general Formula Ic :
• R 13 is dihydroxy(2-4C)alkyl or methoxy(dihydroxy(3-4C)alkyl).
• R 13 is a 1,2-dihydroxy(2-4C alkyl) or a methoxy(1,2-dihydroxy(3-4C)alkyl), such as 3-methoxy-1,2-dihydroxy(3-4C alkyl).
• the alpha carbon of the R 13 group is in the S configuration. In another embodiment, the alpha carbon of the R 13 group is in the R configuration.
• R 13 is selected from the structures:
• R 13 for Formula Ic can be represented by the structures:
• R 2 is pyrid-3-yl, pyrazol-4-yl or pyrazol-5-yl, each of which is optionally substituted with one or more groups independently selected from (1-6C alkyl), for example one or more groups independently selected from methyl and ethyl.
• Particular values for R 2 include the structures:
• R 6 is (1-3C alkoxy)(1-6C alkyl). In one embodiment, R 6 is CH 3 O-(2-3C alkyl)-. Particular values of R 6 for Formula Ic include the structures:
• R 6 is cyclopropyl(1-6 C alkyl)-. In a particular embodiment, R 6 is cyclopropylmethyl.
• R 6 is pyridyl optionally substituted with one or more groups independently selected from (1-6C alkyl). In one embodiment, R 6 is pyridyl-2-yl optionally substituted with one or more groups independently selected from (1-6C alkyl), for example one or more groups independently selected from methyl or ethyl.
• Particular values for R 6 of Formula Ic include the structures:
• Formula I being prepared with the intermediates of the invention also includes a compound of the general Formula Id :
• R 13 is a 1,2-dihydroxy(2-6C)alkyl or a methoxy(1,2-dihydroxy(3-6C)alkyl);
• R 2 is pyrid-3-yl, pyrazol-4-yl or pyrazol-5-yl, each of which is optionally substituted with one or more groups independently selected from (1-6C)alkyl;
• R 6 is methoxy(2-3C alkyl), cyclopropylmethyl, or pyridyl-2-yl optionally substituted with (1-6C alkyl).
• the alpha carbon of the R 13 group is in the S configuration. In another embodiment, the alpha carbon of the R 13 group is in the R configuration.
• R 13 is a 1,2-dihydroxy(2-4C)alkyl or a methoxy(1,2-dihydroxy(3-4C)alkyl), such as 3-methoxy-1,2-dihydroxy(3-4C alkyl).
• R 13 is selected from the structures:
• R 13 for Formula Id can be represented by the structures:
• R 2 is optionally substituted with one to three groups independently selected from (1-6C alkyl), for example one to three groups independently selected from methyl and ethyl.
• Particular values for R 2 include the structures:
• R 6 is methoxy(2-3C alkyl). Particular values include the structures:
• R 6 is cyclopropylmethyl.
• R 6 is pyridyl-2-yl optionally substituted with (1-6C alkyl), for example methyl or ethyl.
• Particular values for R 6 of Formula Id include the structures:
• compounds of Formulas Ic and Id have particularly unexpected and desirable properties.
• the compounds have sufficient solubility, including at low pH, to have dose proportional PK.
• the compounds of Formulas Ic and Id also unexpectedly have low clearance via conjugation reactions.
• the main course of clearance of compounds of Formulas Ic and Id is via hepatic oxidation of the 5-SR 6 moiety and not conjugation to and/or oxidation of the diol moiety. This property diminishes the likelihood of saturation of a clearance mechanism; allowing good predictability of blood levels of the active compound and contributing to dose proportional PK.
• the compounds of Formulas Ic and Id unexpectedly achieve a high oral AUC (area under the plasma drug concentration-time curve after a low oral dose), which results in a greater amount of the compound which is available for binding to the glucokinase enzyme. Together with the linear and dose proportional PK, this allows the therapeutic concentrations of the compound to be reached in a predictable manner.
• certain compounds being prepared with the intermediates according to the invention may contain one or more centers of asymmetry and may therefore be prepared and isolated in a mixture of isomers such as a racemic mixture, or in an enantiomerically pure form.
• the compounds of Formula I being prepared with the intermediates of the invention include pharmaceutically acceptable salts thereof.
• the compounds of Formula I being prepared with the intermediates of the invention also include other salts of such compounds which are not necessarily pharmaceutically acceptable salts, and which may be useful as intermediates for preparing and/or purifying compounds of Formula I and/or for separating enantiomers of compounds of Formula I .
• Compounds of Formula I may be synthesized by synthetic routes that include processes analogous to those well known in the chemical arts, particularly in light of the description contained herein.
• the starting materials are generally available from commercial sources such as Aldrich Chemicals (Milwaukee, WI) or are readily prepared using methods well known to those skilled in the art (e.g., prepared by methods generally described in Louis F. Fieser and Mary Fieser, Reagents for Organic Synthesis, v. 1-19, Wiley, N.Y. (1967-1999 ed.), or Beilsteins Handbuch der organischen Chemie, 4, Aufl. ed. Springer-Verlag, Berlin, including supplements).
• Schemes A-S show general methods for preparing the compounds of Formula I by using the intermediate compounds of the present invention as key intermediates.
• Schemes A-S show general methods for preparing the compounds of Formula I by using the intermediate compounds of the present invention as key intermediates.
• Scheme A shows a method of preparing compounds (3A) of Formula I .
• a 2-aminoheterocycle (1) is reacted with benzoylisothiocyanate to afford a benzoylthiourea intermediate, which is hydrolyzed to the thiourea (2) with a base such as, but not limited to, potassium carbonate in a suitable solvent such as, but not limited to, ethanol.
• the aminoheterocycle (1) can be treated with an inorganic or ammonium isothiocyanate, e.g., Meckler's procedure, in the presence of an acid to afford the thiourea (2) in one step.
• Examples include, but are not limited to, bromination of commercially or readily synthesized methyl ketones ( Tetrahedron (1970) 5611-5615 ; Organic Synthesis (1946) 13-15 ; Tetrahedron (1990) 2943-2964 ), diazomethane treatment of carbonyl chlorides, oxidation of 1-chloro-2-alkanols, bromination of silyl enol ethers, or halogenation of ⁇ -keto esters followed by decarboxylation. After formation of the thiazole (3A), protecting groups, if present, can be removed.
• Scheme B shows an alternative method of preparing a compound of Formula I .
• hydroxylated heteroaryl halide (5) (if not commercially available) can be prepared from heteroaryl halide (4) by: 1) ortho metalation with LDA or another suitable base; 2) conversion of the anion to the boronate via reaction with B(OR) 3 ; and 3) oxidation of the boronate with a suitable oxidant such as N -methylmorpholine oxide or hydrogen peroxide.
• the ortho metalated species can also be quenched with (TMSO) 2 to obtain the hydroxylated material (5) directly upon acidic workup.
• the hydroxylated heteroaromatic compound (5) can be alkylated with R 2 X in the presence of a base such as, but not limited to, cesium carbonate or sodium hydride and in a suitable solvent such as, but not limited to, DMF to afford compound (6).
• Compound (6) can be converted to compound (7) by the method of Hartwig et al. (for an example of this transformation via analogy see: Organic Letters (2001) 2729-2732 ), or by treatment with a Pd catalyst and benzophenone imine, or by heating in the presence of ammonia (or NH 2 PG where PG is a protecting group).
• Compound (7) can be converted to compound (3) of Formula I upon reaction with a halo-substituted thiazole or halo-substituted thiadiazole in the presence of a base catalyst or metal (e.g., copper or palladium) catalyst.
• compound (6) can be converted directly to a compound (3) of Formula I upon treatment with an amino-substituted thiazole or amino-substituted thiadiazole via base catalysis or via copper or palladium catalysis; i.e., the Buchwald reaction. After formation of compound (3), protecting groups, if present, can be removed.
• Scheme C shows a method of preparing 2-aminothiazole and 2-halothiazole intermediates (8) and (9), respectively, which are suitable for use in preparing compounds of Formula I as shown in Scheme B.
• ⁇ -haloketone R 13 COCH 2 X can be treated with thiourea in the presence of a suitable base such as potassium carbonate or triethylamine in an appropriate solvent such as DMF or ethanol to afford aminothiazole (8).
• the aminothiazole (8) can be converted to a diazonium salt intermediate by numerous methods including, but not limited to, treatment with sodium nitrite in acid or isobutyl nitrite.
• Scheme D shows a method of preparing 5-amino-1,2,4-thiadiazole and 5-chloro-1,2,4-thiadiazole intermediates (15) and (16), respectively, which are suitable for use in preparing compounds of Formula I as shown in Scheme B.
• primary amide (14) can be converted into 5-amino-1,2,4 thiadiazole (15) by heating with KSCN in an appropriate solvent such as methanol or ethanol ( Adv. Heterocycl. Chem., (1982) 32, 285 ).
• Formation of the diazonium salt of compound (15), followed by treatment of the in situ diazonium salt with CuCl 2 affords the corresponding 5-chloro-1,2,4-thiadiazole (16).
• Scheme E shows an alternative method of preparing compound (3G) of Formula I .
• the halo-substituted heterocycle (28) (prepared by the method of Scheme A or B) wherein X 1 is Cl, Br or I, is first treated with an appropriate amount of methyl lithium solution to remove exchangeable proton(s), and then transmetalated with an alkyl lithium reagent such as n- BuLi, sec-butyl or tert -butyl lithium, or a Grignard reagent such as, i -PrMg-halide. The resulting anion is then quenched with an electrophile to provide compound (3G). After formation of compound (3G), protecting groups, if present, can be removed.
• Scheme F shows a method of preparing compounds (3H) of Formula I from a halo substituted heterocycle (28).
• the halo-substituted heterocycle (28) prepared by the method of Scheme A or B, can be converted to a thiol (29) via one of several procedures.
• the halo-substituted heterocycle (28) is first treated with an appropriate amount of methyl lithium solution to remove exchangeable proton(s), and then transmetalated with an alkyl lithium reagent such as n-BuLi, sec-butyl or tert -butyl lithium, or a Grignard reagent such as, i-PrMg-halide.
• an alkyl lithium reagent such as n-BuLi, sec-butyl or tert -butyl lithium
• a Grignard reagent such as, i-PrMg-halide.
• the resulting anion is quenched with either elemental sulfur or bis(trimethylsilyl) peroxide to form the corresponding mercapto-substituted compound (29).
• the halide (28) can be converted under Pd-mediated conditions to thiol (29) utilizing potassium triisopropylsilanethiolate ( Tetrahedron Letters (1994) 3225-3226 ).
• the thiol can be reacted with a variety of electrophiles using standard reaction conditions to provide the corresponding ether (3H) of Formula I.
• Suitable electrophiles include, but are not limited to, activated heteroaryl halides such as, but not limited to, 2-fluorocyanobenzene, 4-fluorocyanobenzene, 2-fluoronitrobenzene, 4-fluoronitrobenzene, 2-chloro-4-nitropyridine, 2-halopyridine, 2-halopyrimidine, 4-halopyrimidine, aryl halides and heteroaryl halides.
• activated heteroaryl halides such as, but not limited to, 2-fluorocyanobenzene, 4-fluorocyanobenzene, 2-fluoronitrobenzene, 4-fluoronitrobenzene, 2-chloro-4-nitropyridine, 2-halopyridine, 2-halopyrimidine, 4-halopyrimidine, aryl halides and heteroaryl halides.
• Scheme G shows an alternate method of adding the linker OR 2 to a core heterocycle to provide a compound (3) of Formula I.
• a benzyl ether (32) prepared by the method of Scheme A or B, can be converted to the hydroxyl substituted heterocycle (33), for example by hydrolysis with a strong acid (e.g., 6N HCl) or by hydrogenation (e.g., H 2 or ammonium formate in the presence of a metal catalyst).
• a strong acid e.g., 6N HCl
• hydrogenation e.g., H 2 or ammonium formate in the presence of a metal catalyst.
• Scheme H shows an alternative method of preparing a compound (3L) of Formula I.
• the 2-aminopyridine (38) is regioselectively brominated with a suitable brominating agent such as NBS or bromine to provide compound (39).
• the brominated compound can be converted to compound (40) upon reaction with R 2 LH (wherein L is O) in the presence of a suitable base such as cesium carbonate, sodium hydride or triethylamine in the presence of a metal catalyst (i.e.; Cul or Pd 2 dba 3 ) in a suitable solvent such as DMSO or DMF.
• the chlorinated product (40) can be converted to compound (41) by the method of Scheme A, B or L.
• Compound (41) can be converted to a 5-substituted compound (3L) of Formula I by the method of Scheme E or F.
• the chlorinated 2-aminopyridine (40) can be converted to a 5-substituted compound (42) by the method of Scheme E or F, and then the thiazolyl or thiadiazolyl group can be added to compound (42) by the method of Scheme A, B or L to provide compound (3L).
• protecting groups, if present, can be removed.
• Scheme I shows an alternative method of preparing a compound (3L) of Formula I .
• reaction of compound (43) with R 2 LH (where L is O) in the presence of a suitable base such cesium carbonate or sodium hydride either with or without a metal catalyst (i.e.; Pd 2 dba 3 or Cul) in DMSO or DMF affords compound (44) wherein L is O.
• the 2-aminopyridine (44) is then regioselectively brominated with a suitable brominating agent such as NBS or bromine to provide compound (45).
• a suitable brominating agent such as NBS or bromine
• the brominated product (45) can be converted to compound (46) by the method of Scheme A, B or L.
• Compound (46) can be converted to 5-substituted compounds (3L) of Formula I by the method of Scheme E or F.
• the brominated 2-aminopyridine (45) can be converted to a 5-substituted compound (47) by the method of Scheme E or F, and then the thiazolyl or thiadiazolyl group can be added to compound (47) by the method of Scheme A, B or L to provide compound (3L).
• protecting groups, if present, can be removed.
• Scheme J shows an alternative method of preparing a compound (3L) of Formula I .
• reaction of compound (48) (which if not commercially available can be made from commercial aminopyridines via regioselective bromination) in the presence of a suitable base such cesium carbonate or sodium hydride and with or without a metal catalyst (e.g., Pd 2 dba 3 or Cul) in DMSO or DMF affords compound (49) by a method such as: ipso replacement using R 6 SH; Buchwald thioether formation with R 6 SH, etc., according to procedures well known in the literature.
• a suitable base such cesium carbonate or sodium hydride
• a metal catalyst e.g., Pd 2 dba 3 or Cul
• the 2-aminopyridine (49) is then regioselectively brominated with a suitable brominating agent such as NBS or bromine to provide compound (50).
• a suitable brominating agent such as NBS or bromine
• the brominated product (50) can be converted to compound (51) by the method of Scheme A, B or L.
• Compound (51) can be converted to 5-substituted compounds (3L) of Formula I by Buchwald ether formation with R 2 OH.
• the brominated 2-aminopyridine (50) can first be converted to compound (52) by the Buchwald chemistry, and compound (52) can be converted to compound (3L) by the method of Scheme A, B or L. After formation of compound (3L), protecting groups, if present, can be removed.
• Scheme K shows an alternative method of preparing a compound (3L) of Formula I .
• compound (54) can be regioselectively brominated to afford compound (55).
• This compound can be converted to compound (56) via the methods described in Schemes E or F.
• Compound (56) is then converted to compound (3L) via the procedures found in Schemes A, B or L.
• compound (55) can be converted to compound (57) via the procedures found in Schemes A, B or L, and then converted to compound (3L) via the procedures found in Schemes E or F.
• protecting groups if present, can be removed.
• Scheme L shows an alternative method for producing compounds of the formula 3C wherein D 2 is N.
• Formation of oxime (80) from aldehyde (79) allows for the chlorination with N-chlorosuccinimide in a suitable solvent, such as DMF, to produce compound (81).
• Compound (81) is sulfonylated with a sulfonyl chloride having the formula R'SO 2 Cl wherein R' is, C 1 -C 6 alkyl (for example, methyl) or aryl optionally substituted with C 1 -C 6 alkyl (for example, tolyl) in the presence of a base, such as but not limited to triethylamine, to afford compound (82) (See, for example, Gibbons, L.
• Scheme M shows an alternative method for the construction of compounds of Formula I .
• selective nucleophilic displacement can be achieved with compounds of the formula R 2 LH and an appropriate base, such as sodium hydride, in a suitable solvent, such as DMF to provide compound (85).
• Hydrolysis of the nitrile can occur under many conditions, with NaOH in aqueous ethanol being preferred, to afford the picolinate (87). Curtius rearrangement in the presence of an appropriate alcohol affords the carbamate (88).
• the carbamate can be removed using various conditions, depending on the alcohol used in the previous step, to provide the 2-aminopyridine (89).
• compound (90) of the Formula I can be synthesized from compound (89).
• protecting groups if present, can be removed.
• Scheme N shows another alternative method for the construction of compounds of Formula I .
• selective nucleophilic displacement can be achieved with compounds of the formula R 2 LH and an appropriate base, such as sodium hydride, in a suitable solvent, such as DMF to provide compound ( 85 ).
• Hydrolysis of the nitrile to the amide ( 91 ) can occur under standard conditions, such as with concentrated H 2 SO 4 .
• a Hofmann reaction to convert ( 91 ) to the aminopyridine ( 92 ) can occur under standard conditions, such as with NaOBr.
• compound ( 93 ) of the Formula I can be synthesized from compound ( 92 ). After formation of compound ( 93 ), protecting groups, if present, can be removed.
• Scheme O shows an alternative method for the construction of compounds of Formula I.
• X is Br or Cl
• selective nucleophilic displacement can be achieved with compounds of the formula R 2 LH and an appropriate base, such as sodium hydride, in a suitable solvent, such as DMF to provide compound ( 95 ).
• Hydrolysis of the nitrile to the amide ( 96 ) can occur under standard conditions, such as with concentrated H 2 SO 4 .
• a Hofmann reaction to convert ( 96 ) to the aminopyridine ( 97 ) can occur under standard conditions, such as with NaOBr.
• compound ( 98 ) of the Formula I can be synthesized from compound ( 97 ). After formation of compound ( 98 ), protecting groups, if present, can be removed.
• Scheme P shows a method of synthesizing compounds of Formula I where R 3 is CF 3 (105).
• the 2,3-dichloro-5-(trifluoromethyl)pyridine ( 99 ) is reacted with DMAP, followed by a cyanide source, such as NaCN, to provide the cyanopyridine ( 100 ).
• a cyanide source such as NaCN
• Nucleophilic displacement of the chlorine with compounds of the formula R 2 LH and an appropriate base, such as sodium hydride, in a suitable solvent, such as DMF provides compound ( 101 ).
• the cyanopyridine ( 101 ) can be converted into the aminopyridine ( 103 ).
• compounds ( 105 ) of the Formula I can be synthesized from compound ( 103 ). After formation of compound ( 105 ), protecting groups, if present, can be removed.
• the pendant alkene in compound (106) which can be synthesized from the methods in schemes A, B or L, can be dihydroxylated by a variety of conditions, such as but not limited to, treating compound (106) with an oxidizing agent such as OsO 4 to provide the diol (107).
• compound (107) can be prepared in a chiral manner through the use of reagents or kits such as, but not limited to, AD-mix- ⁇ (K 2 OsO 2 (OH) 4 , (DHQ) 2 -PHAL (a chiral quinine ligand) and either potassium ferricyanide or N-methylmorpholine N-oxide) and AD-mix- ⁇ (K 2 OsO 2 (OH) 4 , (DHQD) 2 -PHAL (a chiral quinine ligand) and either potassium ferricyanide or N-methylmorpholine N-oxide).
• the alkene (106) can be oxidized to the epoxide (108), which can be hydrolyzed to provide the diol (107).
• epoxide ( 108 ) can be opened with a cyanide source, such as NaCN, to afford compound ( 109 ).
• Compound ( 109 ) can be reacted with one or two equivalents of an alkali metal hydride reagent (for example LiAlH 4 , DIBAL-H or BH 3 ) or an organometallic reagent R x M or (R x ) 2 M where M is a metal (for example, R x Li, (R x ) 2 Zn or (R x ) 2 CuLi) to afford compound ( 110 ) or ( 111 ), respectively.
• an alkali metal hydride reagent for example LiAlH 4 , DIBAL-H or BH 3
• compound (110) can be further reduced with an alkali metal hydride reagent (for example LiAlH 4 , DIBAL-H or BH 3 ) or an organometallic reagent R x M or (R X ) 2 M where M is a metal (for example, R x Li, (R x ) 2 Zn or (R x ) 2 CuLi) to afford compound ( 111 ).
• an alkali metal hydride reagent for example LiAlH 4 , DIBAL-H or BH 3
• an organometallic reagent R x M or (R X ) 2 M where M is a metal for example, R x Li, (R x ) 2 Zn or (R x ) 2 CuLi
• Carbonyl compound ( 112 ) which can be synthesized by methods in Schemes A, B or L, can be converted to the cyanohydrin ( 113 ).
• the cyanohydrin ( 113 ) can be treated with 1 or 2 equivalents of an alkali metal hydride reagent (for example LiAlH 4 , DIBAL-H or BH 3 ) or an organometallic reagent R x M or (R x ) 2 M where M is a metal (for example, R x Li, (R x ) 2 Zn or (R x ) 2 CuLi) to provide compound ( 114 ) or ( 115 ), respectively.
• an alkali metal hydride reagent for example LiAlH 4 , DIBAL-H or BH 3
• compound (114) can be further reacted with an alkali metal hydride reagent R x M or (R x ) 2 M where M is a metal (for example LiAlH 4 , DIBAL-H or BH 3 ) or an organometallic reagent (for example, R x Li, (R x ) 2 Zn or (R x ) 2 CuLi) to afford compound ( 115 ).
• R x M or (R x ) 2 M where M is a metal (for example LiAlH 4 , DIBAL-H or BH 3 ) or an organometallic reagent (for example, R x Li, (R x ) 2 Zn or (R x ) 2 CuLi)
• the embodiments of the invention provides intermediates that can be used in a method for preparing a compound of Formula I or a salt thereof, comprising:
• X can be a leaving atom (for example, Cl, Br) or a leaving group (e.g., OTs or OTf).
• X can be a leaving group (such as OTs or NR 3 wherein R is C 1 -C 6 alkyl) or a leaving atom (for example Cl, Br, or I).
• a suitable base may be, for example, an alkyl lithium base such as methyl lithium, butyl lithium, or a mixture thereof.
• X can be a leaving atom such as a halogen (e.g., F, Cl or Br) or a leaving group such as a sulfonate (e.g., OMs or OTs).
• X b may be a leaving atom such as a halogen (e.g., F, Cl or Br) or a leaving group such as a sulfonate (e.g., OMs or OTs).
• a suitable base may be, for example, an alkali metal alkoxide such as potassium t-butoxide.
• X c may be a leaving atom such as a halogen, such as Br, Cl or I.
• a suitable base may be, for example, an alkyl lithium such as methyl lithium, butyl lithium, or a combination thereof.
• X d may be a leaving atom such as a halogen (e.g., F, Cl or Br) or a leaving group such as a sulfonate (e.g., OMs or OTs).
• a halogen e.g., F, Cl or Br
• a leaving group such as a sulfonate (e.g., OMs or OTs).
• X e may be a leaving group or atom e.g., a halogen such as Cl or Br; or a triflate or tosylate group.
• Suitable bases include alkali metal carbonates such as CsCO 3 .
• suitable oxidizing agents include OsO 4 , KMnO 4 , AD-mix- ⁇ , AD-mix- ⁇ and the like.
• the hydrolysis of the epoxide can take place under either acidic or basic conditions.
• suitable metal hydride reagents include LiAlH 4 , DIBAL-H and BH 3 .
• suitable organometallic reagents include alkyl lithium, alkyl zinc, and alkyl cuprate reagents.
• Suitable amino-protecting groups include acetyl, trifluoroacetyl, t-butoxycarbonyl (BOC), benzyloxycarbonyl (CBz) and 9-fluorenylmethyleneoxycarbonyl (Fmoc).
• Suitable amino-protecting groups include acetyl, trifluoroacetyl, t-butoxycarbonyl (BOC), benzyloxycarbonyl (CBz) and 9-fluorenylmethyleneoxycarbonyl (Fmoc).
• the compounds prepared by means of the intermediates of the present invention can be used as prophylactics or therapeutic agents for treating diseases or disorders mediated by deficient levels of glucokinase activity or which can be treated by activating glucokinase including, but not limited to, diabetes mellitus, impaired glucose tolerance, IFG (impaired fasting glucose) and IFG (impaired fasting glycemia), as well as other diseases and disorders such as those discussed below.
• the compounds prepared by means of the intermediates of the present invention can be also used to prevent the progression of the borderline type, impaired glucose tolerance, IFG (impaired fasting glucose) or IFG (impaired fasting glycemia) to diabetes mellitus.
• the compounds prepared by means of the intermediates of the present invention can be also used as prophylactics or therapeutic agents of diabetic complications such as, but not limited to, neuropathy, nephropathy, retinopathy, cataract, macroangiopathy, osteopenia, diabetic hyperosmolar coma), infectious diseases (e.g., respiratory infection, urinary tract infection, gastrointestinal tract infection, dermal soft tissue infection, lower limb infection etc.), diabetic gangrene, xerostomia, decreased sense of hearing, cerebrovascular disease, peripheral circulatory disturbance, etc.
• diabetic complications such as, but not limited to, neuropathy, nephropathy, retinopathy, cataract, macroangiopathy, osteopenia, diabetic hyperosmolar coma
• infectious diseases e.g., respiratory infection, urinary tract infection, gastrointestinal tract infection, dermal soft tissue infection, lower limb infection etc.
• diabetic gangrene e.g., xerostomia, decreased sense of hearing, cerebrovascular disease, peripheral circulatory disturbance
• the compounds prepared by means of the intermediates of the present invention can be also used as prophylactics or therapeutic agents in the treatment of diseases and disorders such as, but not limited to, obesity, metabolic syndrome (syndrome X), hyperinsulinemia, hyperinsulinemia-induced sensory disorder, dyslipoproteinemia (abnormal lipoproteins in the blood) including diabetic dyslipidemia, hyperlipidemia, hyperlipoproteinemia (excess of lipoproteins in the blood) including type I, II-a (hypercholesterolemia), II-b, III, IV (hypertriglyceridemia) and V (hypertriglyceridemia), low HDL levels, high LDL levels, atherosclerosis and its sequelae, vascular restenosis, neurodegenerative disease, depression, CNS disorders, liver steatosis, osteoporosis, hypertension, renal diseases (e.g., diabetic nephropathy, glomerular nephritis, glomerulosclerosis, nephrotic syndrome, hypertens
• the compounds prepared by means of the intermediates of the present invention can be also used as prophylactics or therapeutic agents in the treatment of diseases and disorders such as, but not limited to, osteoporosis, fatty liver, hypertension, insulin resistant syndrome, inflammatory diseases (e.g., chronic rheumatoid arthritis, spondylitis deformans, osteoarthritis, lumbago, gout, postoperative or traumatic inflammation, remission of swelling, neuralgia, pharyngolaryngitis, cystitis, hepatitis (including non-alcoholic steatohepatitis), pneumonia, inflammatory colitis, ulcerative colitis), pancreatitis, visceral obesity syndrome, cachexia (e.g., carcinomatous cachexia, tuberculous cachexia, diabetic cachexia, hemopathic cachexia, endocrinopathic cachexia, infectious cachexia, cachexia induced by acquired immunodeficiency syndrome), polycystic ovary syndrome, muscular dystrophy, tumor (e.g.,
• the compounds prepared by means of the intermediates of the present invention can be used in combination with one or more additional drugs, for example a compound that works by the same or a different mechanism of action, such as insulin preparations, agents for improving insulin resistance, alpha-glucosidase inhibitors, biguanides, insulin secretagogues, dipeptidylpeptidase IV (DPP IV) inhibitors, beta-3 agonists, amylin agonists, phosphotyrosine phosphatase inhibitors, gluconeogenesis inhibitors, sodium-glucose cotransporter inhibitors, known therapeutic agents for diabetic complications, antihyperlipidemic agents, hypotensive agents, and antiobesity agents.
• An example of an agent for improving insulin resistance is an agonist for peroxisome proliferator-activated receptor-gamma (PPAR gamma).
• the compounds prepared by means of the intermediates of the invention may be administered by any convenient route, e.g. into the gastrointestinal tract (e.g. rectally or orally), the nose, lungs, musculature or vasculature or transdermally.
• the compounds may be administered in any convenient administrative form, e.g. tablets, powders, capsules, solutions, dispersions, suspensions, syrups, sprays, suppositories, gels, emulsions, patches etc.
• Such compositions may contain components conventional in pharmaceutical preparations, e.g. diluents, carriers, pH modifiers, sweeteners, bulking agents, and further active agents. If parenteral administration is desired, the compositions will be sterile and in a solution or suspension form suitable for injection or infusion.
• reaction flasks were typically fitted with rubber septa for the introduction of substrates and reagents via syringe. Glassware was oven dried and/or heat dried.
• Step A To a solution of (R)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde (9.0g, 52.9 mmol) in THF (120 mL and 60 mL of water) was added hydroxyl amine hydrochloride (3.73g, 52.9 mmol) and the reaction stirred until clear (10 minutes). Sodium carbonate (2.75g, 25.9 mmol) was added and the reaction stirred overnight at ambient temperature. The reaction was poured into ethyl acetate (500 mL) and the layers were separated.
• Step B To a solution of (S)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde oxime (9.08g, 49 mmol) in DMF (50 mL) was added 1-chloropyrrolidine-2,5-dione (7.20 g, 53.9 mmol) and the reaction stirred overnight at ambient temperature. The reaction was poured into water (500 mL) extracted with ether. The organics were washed with brine and dried over magnesium sulfate. The material was concentrated in vacuo to yield (R)-N-hydroxy-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (10.4 g, 47 mmol, 96.6%).
• Step C To a solution of (R)-N-hydroxy-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (10.4g, 47.3 mmol) cooled to 0 °C in THF (150 mL) was added methanesulfonyl chloride (5.97g, 52.1 mmol) followed by N-ethyl-N-isopropylpropan-2-amine (6.73 g, 52.1 mmol) and the reaction stirred for 1 hr at ambient temperature. The reaction was concentrated in vacuo.
• Step D A flask was charged with 2-methylpyridin-3-ol (3.0 g, 27.5 mmol) and DMF (100 mL). Sodium hydride (0.760 g, 30.2 mmol) was added and stirred for 5 minutes. 5-Bromo-3-nitropicolinonitrile (6.26 g, 27.5 mmol) was added and stirred for 10 minutes. The reaction was poured into a flask containing 300 mL saturated NH 4 Cl and 300 mL water with vigorous stirring. The solids were filtered and dried under high vacuum to afford 5-bromo-3-(2-methylpyridin-3-yloxy)picolinonitrile (7.78 g, 97.6% yield) as light tan solid.
• Step E A flask was charged with 5-bromo-3-(2-methylpyridin-3-yloxy)picolinonitrile (60 g, 207 mmol) and sulfuric acid (203 g, 2068 mmol). The reaction was stirred at ambient temperature overnight. Water (500 mL) was added carefully and neutralized using 50% sodium hydroxide to pH 5.0. The mixture was extracted with dichloromethane and ethyl acetate, dried and concentrated to afford 5-bromo-3-(2-methylpyridin-3-yloxy)picolinamide (63.0 g, 204 mmol, 98.9 % yield) as yellow solid.
• Step F A flask was charged with 2M sodium hydroxide (256 ml, 511 mmol) and cooled to 0 °C. Bromine (7.85 ml, 153 mmol) was added and stirred for 15 minutes. 5-bromo-3-(2-methylpyridin-3-yloxy)picolinamide (31.5 g, 102 mmol) in dioxane (650 mL) was added and stirred at ambient temperature overnight. The aqueous layer was extracted with ethyl acetate and CH 2 Cl 2 .
• Step G (R)-N-(methylsulfonyloxy)-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (1.86 g, 6.25 mmol), pyridine (1.13 g, 14.3 mmol) and sodium thiocyanate (0.58 g, 7.14 mmol) were dissolved in acetonitrile (45 mL). The solution was heated to 40 °C for 40 minutes. 5-bromo-3-(2-methylpyridin-3-yloxy)pyridin-2-amine (1.0 g, 3.57 mmol) was added and the reaction was heated at 60 °C overnight.
• Step H To a solution of (S)-N-(5-bromo-3-(2-methylpyridin-3-yloxy)pyridin-2-yl)-3-(1,4-dioxaspiro[4.5]decan-2-yl)-1,2,4-thiadiazol-5-amine (0.072 g, 0.20 mmol) in methanol (10 mL) was added concentrated HCl (3 drops) and the reaction heated to 80 °C for 3 hr. The reaction was concentrated in vacuo.
• Step A To a solution of 2-methylpyridin-3-ol (0.96 g, 8.8 mmol) in DMF (10 mL) cooled to 0 °C was added NaH (0.35 g, 8.8 mmol) in portions and the reaction warmed to ambient temperature. To this mixture was added 5-bromo-3-nitropicolinonitrile (2.0 g, 8.8 mmol) and the reaction stirred over night at ambient temperature. To the reaction was added thiophenol (0.96 g, 8.8 mmol) and the reaction cooled to 0 °C. NaH (0.35 g, 8.8 mmol) was added and the reaction warmed to ambient temperature and the reaction stirred at ambient temperature overnight.
• Step B (S)-1-(5-(5-phenylthio-3-(2-methylpyridin-3-yloxy)pyridin-2-ylamino)-1,2,4-thiadiazol-3-yl) ethane-1,2-diol (APCI POS 454 M+H) was synthesized following the procedure in Example 1 substituting 5-phenylthio-3-(2-methylpyridin-3-yloxy)picolinonitrile for 5-bromo-3-(2-methylpyridin-3-yloxy)picolinonitrile in step E.
• Step A To dioxanes (50 mL) bubbled continuously with N 2 was added in this order Pd 2 dba 3 (0.041 g, 0.046 mmol), Xanphos (0.055 g, 0.091 mmol), (S)-N-(5-bromo-3-(2-methylpyridin-3-yloxy)pyridin-2-yl)-3-(1,4-dioxaspiro[4.5]decan-2-yl)-1,2,4-thiadiazol-5-amine (0.46 g, 0.091 mmol), ethyl 2-mercaptoacetate (0.11 g, 0.091 mmol) and Hunig's base (0.12 g, 0.091 mmol) and the reaction was heated to 80 °C for 6hr.
• Step B To a solution of (S)-ethyl-2-(6-(3-(1,4-dioxaspiro[4.5]decan-2-yl)1,2,4-thiadiazo-5-ylamino)-5-(2-methylpyridin-3-yloxy)pyridin-3-ylthio)acetate (0.30 g, 0.55 mmol) in THF (20 mL) cooled to 0 °C was added LiAlH 4 (1 M solution in THF) (0.55 mL, 0.55 mmol) and the reaction stirred for 3 hours while warming to ambient temperature. The reaction was quenched by the addition of water and poured into ethyl acetate (100 mL) and the layers were separated.
• Step C (S)-1-(5-(5-(2-hydroxyethylthio)-3-(2-methylpyridin-3-yloxy)pyridine-2-ylamino)-1,2,4-thiadia-zol-3-yl)ethane-1,2-diol (APCI POS 422 M+H) was synthesized following the procedure in example 1 substituting (S) 2-(6-(3-(1,4-dioxaspiro[4.5]decan-2-yl)1,2,4-thiadiazo-5-ylamino)-5-(2-methylpyridin-3-yloxy)pyridine-3-ylthio)ethanol for (S)-N-(5-bromo-3-(2-methylpyridin-3-yloxy)pyridin-2-yl)-3-(1,4-dioxaspiro[4,5]decan-2-yl)-1,2,4-thiadiazol-5-amine in step H.
• Step A A flask was charged with 4-fluorophenol (44 g, 365 mmol) and DMF (500 mL). The reaction was cooled to 0 °C. Sodium hydride (16.6 g, 414 mmol) was added and stirred for 10 minutes. 5-Bromo-3-nitropicolinonitrile (90 g, 395 mmol) was added and the mixture stirred at ambient temperature for 30 minutes. The reaction was poured into a flask containing water (5000 mL) and stirred for 10 minutes. The pH was adjusted to 10 to give 5-bromo-3-(4-fluorophenoxy)-picolinonitrile (121 g, 413 mmol, 105% yield) as a solid.
• Step B To a solution of pyridne-2-thiol (2.5 g, 23 mmol) in DMA (25 mL) cooled to 0 °C was added NaH (0.90 g, 23 mmol) and the reaction stirred at ambient temperature for 20 min, followed by addition of the 5-bromo-3-(4-fluorophenoxy)picolinonitrile (6.6 g, 23 mmol) and stirring over night at ambient temperature. The reaction was poured into water (250 mL) and a solid formed. The solid was collected, washed with water, and dried in vacuo to yield 3-(4-fluorophenoxy)-5-pyridin-2-ylthio)picolinonitrile (5 g, 16 mmol, 70%).
• Step C (S)-1-(5-(3-(4-fluorophenoxy)-5-(pyridin-2-ylthio)pyridin-2-ylamino)-1,2,4-thiadiazol-3-yl) ethane-1,2-diol (APCI POS 458 M+H) was synthesized following the procedure in example 1 substituting 3-(4-fluorophenoxy)-5-(pyridin-2-ylthio)picolinonitrile for 5-bromo-3-(2-methyl-pyridin-3-yloxy)picolinonitrile in step E.
• Step A A flask was charged with 5-bromo-3-(4-fluorophenoxy)picolinonitrile (10 g, 34 mmol) and sulfuric acid (50 mL). The reaction was stirred at ambient temperature overnight. Water (500 mL) was added carefully and the mixture was adjusted to pH 5.0 using 50% sodium hydroxide. The mixture was extracted with dichloromethane and ethyl acetate, dried and concentrated to afford 5-bromo-3-(4-fluorophenoxy)picolinamide (10.6 g, 34 mmol, 100 % yield) as yellow solid.
• Step B A flask was charged with 2M sodium hydroxide (115 ml, 230 mmol) and cooled to 0 °C. Bromine (9.3 g, 58 mmol) was added and the mixture stirred for 15 minutes. 5-bromo-3-(4-fluorophenoxy)picolinamide (15.8 g, 51 mmol) in dioxane (200 mL) was added and the mixture stirred at ambient temperature overnight. The aqueous layer was extracted with ethyl acetate and CH 2 Cl 2 .
• Step C To a solution of the 5-bromo-3-(2-fluorophenoxy)pyridin-2-amine (17 g, 60 mmol, in THF (500 mL) was added benzoyl isothiocyante (9.8 g, 60 mmol) and the reaction stirred at ambient temperature overnight. The reaction was poured into hexanes (2 L), the solid was collected and dried in vacuo to give N-(5-bromo-3-(4-fluorophenoxy)pyridin-2-ylcarbamothioly)benzamide (25 g, 56 mmol, 93% yield).
• Step D To a solution of N-(5-bromo-3-(4-fluorophenoxy)pyridin-2-ylcarbamothioly)benzamide (25 g, 56 mmol) in ethanol (150 mL) was added NaOH (2 M) (56 mL, 112 mmol) and the reaction stirred ON at 80 °C. The mixture was poured into water and the slurry filtered. The collected solid was dried in vacuo to yield 1-(5-bromo-3-(4-fluorophenoxy)pyridin-2-yl)thiourea (15.4 g, 45 mmol).
• Step E To a solution of (S)-methyl 2,2-dimethyl-1,3-dioxolane-4-carboxylate (1.3 g, 8.1 mmol) and chloroiodomethane (4.3 g, 24 mmol) in THF (50 mL) at -78 °C was added a solution of LDA (16.2 mL, 24 mmol) in portions over 10 minutes. The reaction was stirred at -78 °C for 10 minutes. To this mixture was added a 10% solution of acetic acid (50 mL) in THF at -78 °C. After addition, the slurry was warmed to ambient temperature.
• Step F To 1-(5-bromo-3-(4-fluorophenoxy)pyridin-2-yl)thiourea (0.5 g, 1.5 mmol) in ethanol (50 mL) was added (S)-2-chloro-1-(2,2-dimethyl-1,3-dioxolane-4-yl)ethanone (0.34 g, 1.9 mmol) and the reaction stirred at 80 °C for 1 hr. The reaction was poured into water (250 mL) and the filtered. The solid was triturated with ethyl acetate and methanol. The solid was suspended in ethyl acetate (500 mL) and washed with 1 N NaOH (500 mL).
• Step A POCl 3 (12.9 ml, 141.2 mmol) was added to DMF (10.9 ml, 141.2 mmol) at 0 °C. The reaction was immediately warmed to ambient temperature and stirred for 30 minutes. ((2,2-diethoxyethoxy)methyl)benzene (10.6 g, 47.1 mmol) was added as a solution in 80 mL of chloroform. The solution was stirred at 75 °C for 3.5 hours. The solution was cooled, poured over ice water, and neutralized with Na 2 CO 3 . The residue was extracted with chloroform and the organic layer was dried with Na 2 SO 4 and concentrated. The residue was re-dissolved in MeOH (450 mL).
• Step B 2-(4-(benzyloxy)-1H-pyrazol-1-yl)ethanol (1.81 g, 8.3 mmol) was dissolved in THF (15 mL) under nitrogen. Pd/C (0.22 g, 0.21 mmol) was added and the solution was placed under vacuum and charged with a hydrogen balloon. The mixture stirred at ambient temperature overnight under this hydrogen atmosphere. The solution was filtered through GF/F paper and concentrated to give 1-(2-hydroxyethyl)-1H-pyrazol-4-ol (1.8 g, quantitative).
• Step C (S)-1-(5-(5-bromo-3-(1-(2-hydroxyethyl)-1H-pyrazol-4-yloxy)pyridin-2-ylamino)-1,2,4-thiadiazol-3-yl)ethane-1,2-diol (APCI POS 443, 445 M+H) was synthesized following the procedure in Example 1 substituting 1-(2-hydroxyethyl)-1H-pyrazol-4-ol for 2-methylpyridin-3-ol in Step D.
• Step A To 600 mL of DMF in a 4 neck 3000 mL round bottom flask equipped with an overhead stir mechanism under nitrogen was added 2-methylpyridin-3-ol (71.8 g, 658 mmol) and the reaction cooled to 2 °C. 60% sodium hydride (26.3 g, 658 mmol) was added at such a rate that the internal temperature did not exceed 10 °C over a period of 30 minutes. The reaction was stirred while warming to ambient temperature for 1 hour. To the reaction was added 5-bromo-3-nitropicolinonitrile (150 g, 658 mmol) in a solution of 400 mL of DMF in two portions and the reaction held at ambient temperature for 1.5 hours.
• 2-methylpyridin-3-ol 71.8 g, 658 mmol
• 60% sodium hydride (26.3 g, 658 mmol) was added at such a rate that the internal temperature did not exceed 10 °C over a period of 30 minutes.
• the reaction was stirred while warming to ambient temperature
• Step B To concentrated H 2 SO 4 (90 mL) cooled in an ice bath was added 3-(2-methylpyridin-3-yloxy)-5-(pyridin-2-ylthio)picolinonitrile (43 g, 130 mmol) in portions such that the internal temp did not exceed 50 °C but did not go below 25 °C. After complete addition, the mixture was stirred in the ice bath until the reaction started to cool, at which point the reaction was removed from the ice bath and the mixture was heated to 50 °C. The reaction was cooled to ambient temperature and slowly added to ice water over 3 minutes (about 1400 mL of 30% ice in water).
• the mixture was further cooled in an ice bath to 5 °C and neutralized to pH ⁇ 10 with 4M NaOH (about 800 mL) while keeping the internal temperature below 20 °C, at which point a solid formed.
• the mixture was stirred for 20 minutes.
• the mixture was filtered and washed with MTBE (5 x 150 mL), hexanes (5 x 100 mL), and dried at under vacuum to afford 3-(2-methylpyridin-3-yloxy)-5-(pyridin-2-ylthio)picolinamide (43 g, 96%).
• Step C To a 3-neck 2 L round bottom flask was added 2M aqueous sodium hydroxide (343 ml, 686 mmol) and the solution was cooled in an ice bath. Bromine (12 ml, 257 mmol) was added and the mixture was stirred for 30 minutes while the ice bath was removed. 3-(2-Methylpyridin-3-yloxy)-5-(pyridin-2-ylthio)picolinamide (58 g, 171 mmol) was added as a slurry in about 600 mL of dioxane in 1 portion. After 30 minutes, concentrated HCl was added in 1 mL portions to a pH ⁇ 1.
• the reaction was stirred for 15 minutes and 4N NaOH was added to the solution to pH -10.
• the aqueous mixture was extracted with EtOAc (3 x 750 mL), washed with water (2 x 250 mL) and brine (300 mL), dried over MgSO 4 , filtered and concentrated.
• the material was dried in vacuo at 50 °C at which point a red solid formed.
• the solid was triturated with CH 2 Cl 2 (about 40 mL of CH 2 Cl 2 to 5 g of material) and the solid filtered. The solid was washed with CH 2 Cl 2 and dried under vacuum at 50 °C.
• Step D To 1000 mL of DI water was added hydroxyl amine hydrochloride (51.0 g, 734 mmol) and the mixture was stirred for 5 minutes. Sodium carbonate (38.1 g, 360 mmol) was added in 3 large portions and the reaction was stirred for 15 minutes. THF (700 mL) was added to the reaction and (R)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde (125 g, 734 mmol) was added in 1 portion in 800 mL of THF. The reaction was stirred for 4 hours and poured into a 4 L separatory funnel and the layers separated. The aqueous layer was extracted twice with MTBE (about 3000 mL total).
• Step E To a 4-neck 2 L round bottom flask was added (S)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde oxime (135.1 g, 729.4 mmol) and 750 mL of DMF. The reaction was placed in a water bath and 1-chloropyrrolidine-2,5-dione (97.40 g, 729.4 mmol) was added in portions over 2 minutes. The reaction was stirred in the water bath for 3 hours, then diluted with 2L of MTBE and washed with 1L of water. The water was extracted with 500 mL of MTBE.
• Step F In a 4 neck 5 L flask was added (R)-N-hydroxy-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (158 g, 719 mmol) in 2.5 L of THF. The material was cooled to 3 °C and methanesulfonyl chloride (56.1 ml, 719 mmol) added in 10 mL portions over 10 minutes. N-ethyl-N-isopropylpropan-2-amine (126 ml, 719 mmol) was added through an addition funnel over 12 minutes. The reaction was stirred in the ice bath for 30 minutes and then at ambient temperature for 1 hour.
• Step G To 700 mL of acetonitrile was added sodium isothiocyanate (12.5 g, 155 mmol), pyridine (25.2 ml, 309 mmol) and (R)-N-(methylsulfonyloxy)-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (38.4 g, 129 mmol) and the reaction heated to 60 °C for 15 minutes (white solid formed).
• Step H In 1 L of absolute ethanol was added (S)-N-(3-(2-methylpyridin-3-yloxy)-5-(pyridin-2-ylthio)pyridin-2-yl)-3-(1,4-dioxaspiro[4.5]decan-2-yl)-1,2,4-thiadiazol-5-amine (41 g, 76.7 mmol) and the reaction was heated to 80 °C. 41 mL of aqueous HCI (11.6 mL of concentrated HCl diluted in water) was added. After 2 hours, the resultant solid material was hot filtered, washed with ethanol (200 mL) and dried in vacuo to yield crude product as a solid which contained about 2% starting material.
• Step A To a 0 °C solution of 2,6-dimethylpyridin-3-ol (10g, 81.2 mmol) in DMF (50ml) was added sodium hydride (60% dispersion in oil, 3.4 g, 85 mmol). After 15 minutes, 5-bromo-3-nitropicolinonitrile (18.5g, 81 mmol) was added and the mixture was allowed to warm slowly to ambient temperature. The reaction mixture was slowly added to 500 mL of rapidly stirring water. A light red solid formed and then the material formed a gum.
• Step B To 5-bromo-3-(2,6-dimethylpyridin-3-yloxy)picolinonitrile (25g, 82 mmol) was added concentrated sulfuric acid (25ml) and the mixture stirred at ambient temperature over night. The mixture was poured onto ice (500 ml) and the aqueous mixture neutralized using 50% NaOH. A solid formed at pH 7. The solid was collected and dried in vacuo to afford 3-(2,6-dimethylpyridin-3-yloxy)-5-bromopicolinamide (24.2g, 92%).
• Step C To a 0 °C solution of NaOH (150 mL, 2M) was added bromine (14.4g, 90 mmol), followed by 3-(2,6-dimethylpyridin-3-yloxy)-5-bromopicolinamide (24g, 75 mmol) dissolved in dioxanes (300 ml). The reaction was stirred at ambient temperature for 1 hour and then at 80 °C for 1 hour. The reaction was cooled to ambient temperature and acidified to pH 1 with concentrated HCI. The mixture was stirred at ambient temperature for 1 hour and basified to pH 10 using 2M NaOH. The aqueous layer was extracted into ethyl acetate. The combined organic layers were washed with brine, dried over MgSO 4 and concentrated in vacuo to afford 5-bromo-3-(2,6-dimethylpyridin-3-yloxy)pyridin-2-amine (20.5g, 92%).
• Step D A 250 mL flask was charged with 5-bromo-3-(2,6-dimethylpyridin-3-yloxy)pyridin-2-amine (5.00 g, 17.66 mmol) and THF (100 mL) and purged with nitrogen. The solution was cooled to -78 °C, methyl lithium (1.6 M in hexanes, 12.7 mL, 20.4 mmol) was added and the reaction was stirred for 5 minutes. Butyl lithium (2.5 M in Hexanes, 8.1 mL, 20.4 mmol) was added and the reaction was stirred for 10 minutes at -78 °C (solids formed).
• Step E In 1000 mL of DI water was added hydroxyl amine hydrochloride (51.0 g, 734 mmol) and the reaction was stirred for 5 minutes. Sodium carbonate (38.1 g, 360 mmol) was added in 3 large portions and the reaction was stirred for 15 minutes. THF (700 mL) was added to the reaction and (R)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde (125 g, 734 mmol) was added in 1 portion in 800 mL of THF. The reaction was stirred for 4 hours and poured into a 4 L separatory funnel and the layers separated. The aqueous layer was extracted twice with MTBE (about 3000 mL total).
• Step F To a 4-neck 2 L round bottom flask was added (S)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde oxime (135.1 g, 729.4 mmol) and dissolved in 750 mL of DMF. The reaction was placed in a water bath and 1-chloropyrrolidine-2,5-dione (97.40 g, 729.4 mmol) was added in portions over 2 minutes. The reaction was stirred in the water bath for 3 hours, then diluted with 2 L of MTBE and washed with 1 L of water. The water was extracted with 500 mL of MTBE.
• Step G In a 4 neck 5 L flask was added (R)-N-hydroxy-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (158 g, 719 mmol) in 2.5 L of THF. The material was cooled to 3 °C and methanesulfonyl chloride (56.1 ml, 719 mmol) added in 10 mL portions over 10 minutes. Next, N-ethyl-N-isopropylpropan-2-amine (126 ml, 719 mmol) was added through an addition funnel over 12 minutes. The reaction was stirred in the ice bath for 30 minutes and then at ambient temperature for 1 hour.
• Step H To a solution of sodium isothiocyanate (0.24 g, 3.0 mmol) in acetonitrile (30 mL) was added pyridine (0.51 g, 6.5 mmol) followed by (R)-N-(methylsulfonyloxy)-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (0.77 g, 2.6 mmol) and the reaction was stirred at 60 °C for 20 minutes, followed by addition of 3-(2,6-dimethylpyridin-3-yloxy)-5-(pyridin-2-ylthio)pyridin-2-amine (0.70 g, 2.2 mmol) and the reaction was stirred overnight at 60 °C.
• Step A To a solution of 2-methylpyridin-3-ol (11.8 g, 108 mmol) in DMF at 0 °C was added sodium hydride (60% dispersion in oil, 4.32 g, 108 mmol) in small portions and the reaction was warmed to ambient temperature. To this mixture was added 5-bromo-3-nitropicolinonitrile (24.6 g, 108 mmol) and the reaction was stirred overnight at ambient temperature. The reaction was poured into water (1000 mL) and the aqueous layer extracted with EtOAc. The combined organic layers were washed with water (3x) and brine, dried over MgSO 4 and concentrated in vacuo to yield 5-bromo-3-(2-methylpyridin-3-yloxy)picolinonitrile (15 g, 48%).
• sodium hydride 50% dispersion in oil, 4.32 g, 108 mmol
• Step B To 5-bromo-3-(2-methylpyridin-3-yloxy)picolinonitrile (15 g, 52 mmol) was added concentrated H 2 SO 4 (30 mL) and the slurry was left to stir overnight, at which point the material was fully dissolved. The reaction was poured into 0 °C water in small portions. While maintaining the temp below 20 °C, the aqueous layer was basified by the addition of NaOH pellets, to a pH of ⁇ 5, at which point a solid formed. The solid was filtered and the remaining aqueous layer was extracted with EtOAc. The organic layers, combined with the solid, were washed with brine, dried over MgSO 4 and concentrated in vacuo to yield 5-bromo-3-(2-methylpyridin-3-yloxy)picolinamide (11g, 69%).
• Step C To a solution of NaOH (2M, 90 mL, 182 mmol) at 0 °C was added bromine (8.71 g, 54 mmol) and the reaction was stirred at 0 °C for 30 minutes. To this mixture was added 5-bromo-3-(2-methylpyridin-3-yloxy)picolinamide (11.2g, 36.3 mmol) in dioxanes (100 mL) and the reaction was stirred at ambient temperature for 1 hour followed by heating to 80 °C for 1 hour. The reaction was cooled to ambient temperature and acidified to pH 1 using concentrated HCI. The reaction was basified and a solid precipitated. The solid was filtered and dried in vacuo to yield 5-bromo-3-(2-methylpyridin-3-yloxy)pyridin-2-amine (4.1 g, 41%).
• Step D In 1000 mL of DI water was added hydroxyl amine hydrochloride (51.0 g, 734 mmol) and the reaction was stirred for 5 minutes. Sodium carbonate (38.1 g, 360 mmol) was added in 3 large portions and the reaction was stirred for 15 minutes. THF (700 mL) was added to the reaction and (R)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde (125 g, 734 mmol) in 800 mL of THF was added in 1 portion. The reaction was stirred for 4 hours, then poured into a 4 L separatory funnel. The layers separated and the aqueous layer was extracted twice with MTBE (about 3000 mL total).
• Step E To a 4-neck 2 L round bottom flask was added (S)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde oxime (135.1 g, 729.4 mmol) dissolved in 750 mL of DMF. The reaction was placed in a water bath and 1-chloropyrrolidine-2,5-dione (97.40 g, 729.4 mmol) was added in portions over 2 minutes. The reaction was stirred in the water bath for 3 hours. The reaction was diluted with 2 L of MTBE and washed with 1 L of water. The water was extracted with 500 mL of MTBE.
• Step F In a 4 neck 5 L flask was added (R)-N-hydroxy-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (158 g, 719 mmol) in 2.5 L of THF. The material was cooled to 3 °C and methanesulfonyl chloride (56.1 ml, 719 mmol) added in 10 mL portions over 10 minutes. Next, N-ethyl-N-isopropylpropan-2-amine (126 ml, 719 mmol) was added through an addition funnel over 12 minutes. The reaction was stirred in the ice bath for 30 minutes and then at ambient temperature for 1 hour.
• Step G In 100 mL of acetonitrile was added sodium thioisocyanate (1.5 g, 20 mmol), pyridine (3.5g, 44 mmol), followed by (R)-N-(methylsulfonyloxy)-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (5.2g, 18 mmol) and the reaction was heated to 60 °C for 30 minutes. 5-Bromo-3-(2-methylpyridin-3-yloxy)pyridin-2-amine (4.1 g, 15 mmol) was added and the reaction was heated overnight at 60 °C.
• Step H To a solution of (S)-N-(5-bromo-3-(2-methylpyridin-3-yloxy)pyridin-2-yl)-3-(1,4-dioxaspiro[4.5]decan-2-yl)-1,2,4-thiadiazol-5-amine (3.1g, 6.14 mmol) in dioxanes (30 mL) continuously purged with nitrogen was added Xanphos (0.177 g, 0.303 mmol), Pd 2 dba 3 (0.14 g, 0.153 mmol), methyl 3-mercaptopropanoate (0.73 g, 6.14 mmol) and N,N-diisopropylethylamine (1.17 mL, 6.45 mmol) and the reaction heated overnight at 80 °C.
• Step I To a solution of (S)-methyl 3-(6-(3-(1,4-dioxaspiro[4.5]decan-2-yl)-1,2,4-thiadiazol-5-ylamino)-5-(2-methylpyridin-3-yloxy)pyridin-3-ylthio)propanoate (0.428 g, 0.787 mmol) in THF (20 mL) was added potassium 2-methylpropan-2-olate (1M in THF, 2.36 ml, 2.36 mmol) and the reaction was stirred at ambient temperature for 5 minutes.
• Step J To a solution of (S)-N-(5-(cyclopropylmethylthio)-3-(2-methylpyridin-3-yloxy)pyridin-2-yl)-3-(1,4-dioxaspiro[4.5]decan-2-yl)-1,2,4-thiadiazol-5-amine (0.30 g, 0.586 mmol) in ethanol (20 mL) was added 1 M HCI (0.87 mL) and the reaction heated to 80 °C for 2 hours. The reaction was cooled and concentrated in vacuo and the solid triturated with ethanol.
• Step A 2-Bromopyridin-3-yl acetate (10 g, 46 mmol) was dissolved in THF (80 mL) and triethylamine (32 ml, 231 mmol), ethynyltrimethylsilane (19.5 ml, 139 mmol), and Cul (0.44 g, 2.3 mmol) were added. The mixture was degassed with argon for 15 minutes, then PdCl 2 (PPh 3 ) 2 (1.6 g, 2.3 mmol) was added and the mixture was stirred under argon at ambient temperature for 18 hours.
• PdCl 2 (PPh 3 ) 2 1.6 g, 2.3 mmol
• Step B To a solution of 2-((trimethylsilyl)ethynyl)pyridin-3-yl acetate (9.5 g, 41 mmol) in THF (200 mL) was added water (25 ml). The reaction was cooled to 0 °C and TBAF (1 M, 45 ml, 45 mmol) was added. The mixture warmed to ambient temperature and stirred for 1 hour. Water (100 mL) was added and the volume was reduced by half. The product was extracted into ether (3 x 100mL), washed with brine and dried over MgSO 4 . The solution was concentrated in vacuo to afford 2-ethynylpyridin-3-yl acetate (5.5 g, 34 mmol) as a light brown oil.
• Step C To a solution of 2-ethynylpyridin-3-yl acetate (5.0 g, 31 mmol) in ethanol (50 mL) was added PtO 2 (0.50 g, 2.2 mmol). The mixture was degassed with nitrogen and placed under a double-layer balloon of hydrogen. The reaction was stirred at ambient temperature for 30 minutes, then filtered and concentrated in vacuo to give 2-ethylpyridin-3-yl acetate (5.1 g, 31 mmol) which was used in the next step without further purification.
• Step D To a solution of 2-ethylpyridin-3-yl acetate (5.1 g, 31 mmol) in ethanol (50 mL) was added 3M LiOH (50 mL, 150 mmol). The reaction mixture stirred at ambient temperature for 30 minutes. The mixture was concentrated to dryness and purified over silica gel (10% MeOH in CH 2 Cl 2 ) to afford 2-ethylpyridin-3-ol (2.5 g, 20 mmol).
• Step E To a solution of 2-ethylpyridin-3-ol (2.5 g, 20.3 mmol) in DMF (20 ml) at 0 °C was added sodium hydride (0.512 g, 21.3 mmol). After 15 minutes, 5-bromo-3-nitropicolinonitrile (4.63 g, 20.3 mmol) was added and the mixture was allowed to warm slowly to ambient temperature and stirred for 2 hours. Pridine-2-thiol (0.804 g, 7.23 mmol) was added followed by sodium hydride (0.182 g, 7.60 mmol) and the mixture was stirred at ambient temperature overnight.
• Step F 3-(2-Ethylpyridin-3-yloxy)-5-(pyridin-2-ylthio)picolinonitrile (1.4 g, 4.19 mmol) was stirred in concentrated sulfuric acid (10 mL) overnight at ambient temperature. Ice (100 g) was added and the solution was neutralized using 4M NaOH. Ice was added as necessary to maintain the temperature below 20 °C. The product was extracted into ethyl acetate, washed with brine, dried over MgSO 4 , filtered and concentrated to afford 3-(2-ethylpyridin-3-yloxy)-5-(pyridin-2-ylthio)picolinamide (1.5g, 4.2 mmol).
• Step G A 1M solution of NaOH (10.6 ml, 21.2 mmol) was cooled to 0 °C and bromine (0.38 ml, 7.4 mmol) was added. This mixture stirred at ambient temperature for 30 minutes. Dioxane (15 mL) was added followed by 3-(2-ethylpyridin-3-yloxy)-5-(pyridin-2-ylthio)picolinamide (1.50 g, 4.25 mmol). The mixture stirred at ambient temperature for 30 minutes. Concentrated HCI was added until the solution was pH 1 and the mixture stirred for 5 minutes. The reaction was made basic with 1M NaOH and the product was extracted into ethyl acetate (3 x 100 mL).
• Step H In 1000 mL of DI water was added hydroxyl amine hydrochloride (51.0 g, 734 mmol) and the reaction was stirred for 5 minutes. Sodium carbonate (38.1 g, 360 mmol) was added in 3 large portions and the reaction was stirred for 15 minutes. THF (700 mL) was added to the reaction and (R)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde (125 g, 734 mmol) was added in 1 portion in 800 mL of THF. The reaction was stirred for 4 hours, then poured into a 4 L separatory funnel and the layers separated. The aqueous layer was extracted twice with MTBE (about 3000 mL total).
• Step I To a 4-neck 2 L round bottom flask was added (S)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde oxime (135.1 g, 729.4 mmol) and 750 mL of DMF. The reaction was placed in a water bath and 1-chloropyrrolidine-2,5-dione (97.40 g, 729.4 mmol) was added in portions over 2 minutes. The reaction was stirred in the water bath for 3 hours. The reaction was diluted with 2 L of MTBE and washed with 1 L of water.
• Step J To a 4 neck 5 L flask was added (R)-N-hydroxy-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (158 g, 719 mmol) in 2.5 L of THF. The material was cooled to 3 °C and methanesulfonyl chloride (56.1 ml, 719 mmol) added in 10 mL portions over 10 minutes. Next, N-ethyl-N-isopropylpropan-2-amine (126 ml, 719 mmol) was added through an addition funnel over 12 minutes. The reaction was stirred in the ice bath for 30 minutes and then at ambient temperature for 1 hour.
• Step K (R)-N-(methylsulfonyloxy)-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (0.854 g, 2.87 mmol), pyridine (0.618 ml, 7.64 mmol), and sodium thiocyanate (0.310 g, 3.82 mmol) were dissolved in acetonitrile (10 mL). The solution was heated to 60 °C for 30 minutes. 3-(2-ethylpyridin-3-yloxy)-5-(pyridin-2-ylthio)pyridin-2-amine (0.620 g, 1.91 mmol) was added and the reaction was heated at 60 °C overnight.
• Step L (S)-N-(3-(2-ethylpyridin-3-yloxy)-5-(pyridin-2-ylthio)pyridin-2-yl)-3-(1,4-dioxaspiro[4.5]decan-2-yl)-1,2,4-thiadiazol-5-amine (0.600 g, 1.09 mmol) was dissolved in ethanol (25 ml) and water (600 mg) and concentrated HCl (600 mg) were added. The mixture was heated to reflux for 2 hours, concentrated in vacuo, dissolved and concentrated with EtOH (2 x 50 mL).
• Step A To a solution of 2-methylpyridin-3-ol (11.8 g, 108 mmol) in DMF at 0 °C was added sodium hydride (60% dispersion in oil, 4.32 g, 108 mmol) in small portions and the reaction warmed to ambient temperature. To this mixture was added 5-bromo-3-nitropicolinonitrile (24.6 g, 108 mmol) and the reaction was stirred overnight at ambient temperature. The reaction was poured into water (1000 mL) and the aqueous layer extracted with EtOAc. The combined organic layers were washed with water and brine, dried over MgSO 4 and concentrated in vacuo to yield 5-bromo-3-(2-methylpyridin-3-yloxy)picolinonitrile (15g, 48%).
• sodium hydride 50% dispersion in oil, 4.32 g, 108 mmol
• Step B To 5-bromo-3-(2-methylpyridin-3-yloxy)picolinonitrile (15 g, 52 mmol) was added concentrated H 2 SO 4 (30 mL) and the slurry was stirred overnight, at which point the material was fully dissolved. The reaction was poured into 0 °C water in small portions. While maintaining the temp below 20 °C, the aqueous layer was basified to about a pH of 5 by the addition of NaOH pellets, at which point a solid formed. The solid was filtered, and the remaining aqueous layer was extracted with EtOAc. The organics layers, combined with the solid, were washed with brine, dried over MgSO 4 and concentrated in vacuo to yield 5-bromo-3-(2-methylpyridin-3-yloxy)picolinamide (11g, 69%).
• Step C To a solution of NaOH (2M, 90 mL, 182 mmol) at 0 °C was added bromine (8.71 g, 54 mmol) and the reaction was stirred at 0 °C for 30 minutes. To this mixture was added 5-bromo-3-(2-methylpyridin-3-yloxy)picolinamide (11.2 g, 36.3 mmol) in dioxanes (100 mL) and the reaction was stirred at ambient temperature for 1 hour followed by heating to 80 °C for 1 hour. The reaction was cooled to ambient temperature and acidified to pH 1 using concentrated HCI. The reaction was basified and a solid precipitated. The solid was filtered and dried in vacuo to yield product 5-bromo-3-(2-methylpyridin-3-yloxy)pyridin-2-amine (4.1 g, 41%).
• Step D In 1000 mL of DI water was added hydroxyl amine hydrochloride (51.0 g, 734 mmol) and the reaction was stirred for 5 minutes. Sodium carbonate (38.1 g, 360 mmol) was added in 3 large portions and the reaction was stirred for 15 minutes. THF (700 mL) was added to the reaction and (R)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde (125 g, 734 mmol) was added in 1 portion in 800 mL of THF. The reaction was stirred for 4 hours and poured into a 4 L separatory funnel and the layers separated. The aqueous layer was extracted twice with MTBE (about 3000 mL total).
• Step E To a 4-neck 2 L round bottom flask was added (S)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde oxime (135.1 g, 729.4 mmol) dissolved in 750 mL of DMF. The reaction was placed in a water bath and 1-chloropyrrolidine-2,5-dione (97.40 g, 729.4 mmol) was added in portions over 2 minutes. The reaction was stirred in the water bath for 3 hours, then diluted with 2L of MTBE and washed with 1L of water. The water was extracted with 500 mL of MTBE.
• Step F In a 4 neck 5 L flask was added (R)-N-hydroxy-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (158 g, 719 mmol) in 2.5 L of THF. The material was cooled to 3 °C and methanesulfonyl chloride (56.1 ml, 719 mmol) added in 10 mL portions over 10 minutes. Next, N-ethyl-N-isopropylpropan-2-amine (126 ml, 719 mmol) was added through an addition funnel over 12 minutes. The reaction was stirred in the ice bath for 30 minutes and then at ambient temperature for 1 hour.
• Step G In 100 mL of acetonitrile was added sodium thioisocyanate (1.5 g, 20 mmol), pyridine (3.5g, 44 mmol), followed by (R)-N-(methylsulfonyloxy)-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (5.2g, 18 mmol) and the reaction was heated to 60 °C for 30 minutes. 5-Bromo-3-(2-methylpyridin-3-yloxy)pyridin-2-amine (4.1g, 15 mmol) was added and the reaction was heated overnight at 60 °C.
• Step H To a solution of (S)-N-(5-bromo-3-(2-methylpyridin-3-yloxy)pyridin-2-yl)-3-(1,4-dioxaspiro[4.5]decan-2-yl)-1,2,4-thiadiazol-5-amine (3.1 g, 6.14 mmol) in dioxanes (30 mL) continuously purged with nitrogen was added Xanphos (0.177 g, 0.303 mmol), Pd 2 dba 3 (0.14 g, 0.153 mmol), methyl 3-mercaptopropanoate (0.73 g, 6.14 mmol) and N,N-diisopropylethylamine (1.17 mL, 6.45 mmol) and the reaction was heated overnight at 80 °C.
• Step I (S)-Methyl 3-(6-(3-(1,4-dioxaspiro[4.5]decan-2-yl)-1,2,4-thiadiazol-5-ylamino)-5-(2-methylpyridin-3-yloxy)pyridin-3-ylthio)propanoate (105 mg, 0.19 mmol) was dissolved in THF (5 ml) and KOtBu (65 mg, 0.58 mmol) was added. The mixture was agitated for 30 minutes and 1-bromo-3-methoxypropane (37 mg, 0.24 mmol) was added.
• Step J (S)-N-(5-(3-methoxypropylthio)-3-(2-methylpyridin-3-yloxy)pyridin-2-yl)-3-(1,4-dioxaspiro[4.5]decan-2-yl)-1,2,4-thiadiazol-5-amine (85 mg, 0.16 mmol) was dissolved in ethanol (5 ml) and 1M HCI (0.5 ml) was added. The mixture was heated to 70 °C and agitated 3 hours. Upon cooling, the reaction was diluted with ethyl acetate, basified with sodium carbonate solution and washed with water and brine, dried (MgSO 4 ), filtered and evaporated.
• Step A In 1L glass beaker, ethylhydrazine oxalate (51.4 g, 342 mmol) was combined with water (300 ml). To the resulting slurry was added a 50% w/v NaOH solution (75.5 g) to adjust the pH to 9.5 (by pH-meter). The mixture was heated to 40 °C and methyl trans-3-methoxyacrylate (24.5 ml, 228 mmol) was added dropwise over 1 hour. The pH was adjusted periodically to 9.0-9.5 range by addition of 50 % w/v NaOH solution. After the completion of addition, the mixture was agitated for additional 3 hours at 40 °C and the pH was adjusted occasionally to about 9.0-9.5.
• Step B 5-Bromo-3-nitropicolinonitrile (24.0 g, 105 mmol), 1-ethyl-1H-pyrazol-5-ol (13.0 g, 116 mmol), and sodium carbonate (11.2 g, 105 mmol) were combined with acetonitrile (400 ml). The mixture was heated to reflux for 20 hours, then cooled to ambient temperature, filtered and evaporated. The residue was dissolved in ethyl acetate (800 ml) and washed with water (3 x 200 ml) and brine, dried (MgSO 4 ), filtered and evaporated.
• Step C 5-Bromo-3-(1-ethyl-1H-pyrazol-5-yloxy)picolinonitrile (16.1 g, 55 mmol) and cesium carbonate (17.9 g, 55 mmol) were combined with DMF (160 ml) and pyridine-2-thiol (6.1 g, 55 mmol) dissolved in DMF (40 ml) was added dropwise over 30 minutes. The mixture was agitated for 1 hour, quenched with saturated ammonium chloride solution and extracted with ethyl acetate. The combined organic extracts were washed with water and brine, dried (MgSO 4 ), filtered and evaporated.
• Step D 3-(1-Ethyl-1H-pyrazol-5-yloxy)-5-(pyridin-2-ylthio)picolinonitrile (16.6 g, 51.33 mmol) was cooled to -10 °C and concentrated HCI (120 ml, 1440 mmol) cooled to the same temperature was added slowly. The mixture was agitated in the cooling bath until the solids were mostly dissolved (30 minutes). The bath was removed and the mixture was agitated for 24 hours. The mixture was then cooled to -10 °C and a mixture of ice (150 g) and 50% w/v NaOH (120 ml) was added slowly, keeping the temperature below 20 °C, to adjust the pH to about 12-13.
• Step E A 3 M solution of KOH (15.99 ml, 47.98 mmol) was chilled in a 0 °C bath, bromine (0.5120 ml, 9.996 mmol) was added in one portion and the mixture was stirred 15 minutes. A solution of 3-(1-ethyl-1H-pyrazol-5-yloxy)-5-(pyridin-2-ylthio)picolinamide (1.365 g, 3.998 mmol) dissolved in dioxane (10 ml) was added, and the resulting mixture was stirred overnight at ambient temperature. The majority of the dioxane was removed in vacuo and the resulting aqueous mixture was extracted with EtOAc.
• Step F In 1000 mL of DI water was added hydroxyl amine hydrochloride (51.0 g, 734 mmol) and the reaction was stirred for 5 minutes. Sodium carbonate (38.1 g, 360 mmol) was added in 3 large portions and the reaction was stirred for 15 minutes. THF (700 mL) was added to the reaction and (R)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde (125 g, 734 mmol) was added in 1 portion in 800 mL of THF. The reaction was stirred for 4 hours and poured into a 4 L separatory funnel and the layers separated. The aqueous layer was extracted twice with MTBE (about 3000 mL total).
• Step G To a 4-neck 2 L round bottom flask was added (S)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde oxime (135.1 g, 729.4 mmol) dissolved in 750 mL of DMF. The reaction was placed in a water bath and 1-chloropyrrolidine-2,5-dione (97.40 g, 729.4 mmol) was added in portions over 2 minutes. The reaction was stirred in the water bath for 3 hours, then diluted with 2 L of MTBE and washed with 1 L of water. The water was extracted with 500 mL of MTBE.
• Step H In a 4 neck 5 L flask was added (R)-N-hydroxy-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (158 g, 719 mmol) in 2.5 L of THF. The material was cooled to 3 °C and methanesulfonyl chloride (56.1 ml, 719 mmol) added in 10 mL portions over 10 minutes. Next, N-ethyl-N-isopropylpropan-2-amine (126 ml, 719 mmol) was added through an addition funnel over 12 minutes. The reaction was stirred in the ice bath for 30 minutes and then at ambient temperature for 1 hour.
• Step I To 75 mL of EtOAc was added sodium isothiocyanate (0.579 g, 7.15 mmol), pyridine (0.874 ml, 10.7 mmol) and (R)-N-(methylsulfonyloxy)-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (2.13 g, 7.15 mmol) and the reaction was heated to 50 °C for 30 minutes.
• sodium isothiocyanate 0.579 g, 7.15 mmol
• pyridine 0.874 ml, 10.7 mmol
• (R)-N-(methylsulfonyloxy)-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (2.13 g, 7.15 mmol)
• the reaction mixture was added to 3-(1-ethyl-1H-pyrazol-5-yloxy)-5-(pyridin-2-ylthio)pyridin-2-amine (1.12 g, 3.57 mmol) and the reaction was stirred for 65 hours at 75 °C.
• the reaction was cooled and diluted with 50 ml EtOAc and 75 ml 1N NaOH.
• the aqueous layer was extracted with EtOAc.
• the organic layer was dried over Na 2 SO 4 , filtered and concentrated.
• Step J To a mixture of (S)-N-(3-(1-ethyl-1H-pyrazol-5-yloxy)-5-(pyridin-2-ylthio)pyridin-2-yl)-3-(1,4-dioxaspiro[4.5]decan-2-yl)-1,2,4-thiadiazol-5-amine (1.24 g, 2.31 mmol) in EtOH (25 ml) and H 2 O (1.09 ml, 2.31 mmol) was added concentrated HCI (0.480 ml, 5.77 mmol) and the reaction was heated at reflux for 8 hours. The reaction was allowed to cool to ambient temperature and stirred overnight.
• Step A In 1L glass beaker, ethylhydrazine oxalate (51.4 g, 342 mmol) was combined with water (300 ml). To the resulting slurry, 50% w/v NaOH solution was added (75.5 g) to adjust the pH to 9.5 (by pH-meter). The mixture was heated to 40 °C and methyl trans-3-methoxyacrylate (24.5 ml, 228 mmol) was added dropwise over 1 hour. The pH was adjusted periodically to about 9.0-9.5 by the addition of a 50 % w/v NaOH solution. After the completion of addition, the mixture was agitated for additional 3 hours at 40 °C and the pH was adjusted occasionally to about 9.0-9.5.
• the mixture was cooled to 5 °C and filtered.
• the filtrate was evaporated to about 150 ml , cooled to 5 °C and filtered.
• the filtrate was acidified to pH 3-4 with 6M HCI (45 ml) and extracted 8 times with a 3:1 mixture of chloroform/isopropanol.
• the combined extracts were dried (MgSO 4 ), filtered and concentrated.
• the crude product was purified over silica gel (20 % MeOH/EtOAc) to afford 1-ethyl-1H-pyrazol-5-ol (18.3 g, 71 % yield) as a yellow solid.
• Step B 5-Bromo-3-nitropicolinonitrile (24.0 g, 105 mmol), 1-ethyl-1H-pyrazol-5-ol (13.0 g, 116 mmol), and sodium carbonate (11.2 g, 105 mmol) were combined with acetonitrile (400 ml). The mixture was heated to reflux for 20 hours. The mixture was then cooled to ambient temperature, filtered and evaporated. The residue was dissolved in ethyl acetate (800 ml) and washed with water (3 x 200 ml) and brine, dried (MgSO 4 ), filtered and evaporated.
• Step C 5-Bromo-3-(1-ethyl-1H-pyrazol-5-yloxy)picolinonitrile (16.1 g, 55 mmol) and cesium carbonate (17.9 g, 55 mmol) were combined with DMF (160 ml) and pyridine-2-thiol (6.1 g, 55 mmol) dissolved in DMF (40 ml) was added dropwise over 30 minutes. The mixture was then agitated for 1 hour, quenched with saturated ammonium chloride solution and extracted with ethyl acetate. The combined organic extracts were washed with water and brine, dried (MgSO 4 ), filtered and evaporated.
• Step D Preparation of 3-(1-ethyl-1H-pyrazol-5-yloxy)-5-(pyridin-2-ylthio)picolinamide: 3-(1-Ethyl-1H-pyrazol-5-yloxy)-5-(pyridin-2-ylthio)picolinonitrile (16.6 g, 51.33 mmol) was cooled to -10 °C and concentrated HCI (120 ml, 1440 mmol) cooled to the same temperature was added slowly. The mixture was agitated in the cooling bath until solids mostly dissolved (30 minutes). The bath was removed and the mixture was agitated for 24 hours.
• Step E A 3 M solution of KOH (15.99 ml, 47.98 mmol) was chilled in a 0 °C bath, bromine (0.5120 ml, 9.996 mmol) was added in one portion and the mixture was stirred 15 minutes. A solution of 3-(1-ethyl-1H-pyrazol-5-yloxy)-5-(pyridin-2-ylthio)picolinamide (1.365 g, 3.998 mmol) dissolved in dioxane (10 ml) was added. The resulting mixture was then stirred overnight at ambient temperature.
• Step F (R)-2,2,5,5-Tetramethyl-1,3-dioxolane-4-carbaldehyde (16 g, 101 mmol) ( Burger, A. Synthesis 1989, (2) 93-97 ) was dissolved in 1:1 methanol:water (250 mL), and hydroxylamine hydrochloride (7.0 g, 101 mmol) and Na 2 CO 3 (5.4 g, 51 mmol) were added and the reaction was stirred at ambient temperature for 2 hours.
• Step G (S)-2,2,5,5-Tetramethyl-1,3-dioxolane-4-carbaldehyde oxime (13 g, 75.1 mmol) was dissolved in DMF (200 mL) and cooled in an ice bath. 1-Chloropyrrolidine-2,5-dione (10.0 g, 75.1 mmol) was added and the reaction was stirred overnight while slowly warming to ambient temperature. The pale yellow solution was poured into water (1.5 L) and extracted with EtOAc. The organic layers were washed with water and brine, dried, filtered and concentrated.
• Step H (R)-N-hydroxy-2,2,5,5-tetramethyl-1,3-dioxolane-4-carbimidoyl chloride (12.4 g, 59.7 mmol) was dissolved in Et 2 O (200 mL) and cooled in an ice bath. Methanesulfonyl chloride (4.6 ml, 59.7 mmol) was added. Triethylamine (8.3 ml, 59.7 mmol) was added slowly and the reaction was stirred in an ice bath for 30 minutes. The reaction was filtered and concentrated.
• Step I To 30 mL of EtOAc was added sodium isothiocyanate (0.0970 g, 1.20 mmol), pyridine (0.195 ml, 2.39 mmol) and (R)-2,2,5,5-tetramethyl-N-(methylsulfonyloxy)-1,3-dioxolane-4-carbimidoyl chloride (0.342 g, 1.20 mmol). The reaction was heated to 60 °C for 15 minutes.
• Step J To a mixture of (S)-N-(3-(1-ethyl-1H-pyrazol-5-yloxy)-5-(pyridin-2-ylthio)pyridin-2-yl)-3-(2,2,5,5-tetramethyl-1,3-dioxolan-4-yl)-1,2,4-thiadiazol-5-amine (0.134 g, 0.255 mmol) in EtOH (5 ml) and water (0.227 ml, 0.255 mmol) was added concentrated HCI (0.0531 ml, 0.637 mmol) and the reaction heated at reflux for 5 hours. The reaction was concentrated to a residue that was partitioned between EtOAc and saturated aqueous NaHCO 3 solution.
• Step A Thiourea (22.1 g, 291 mmol) was added to a solution of 2-bromo-3-methylpyridine (25.0 g, 145 mmol) in ethanol (500 mL) and refluxed overnight. The reaction was cooled to ambient temperature, and a 25% aqueous solution of sodium hydroxide (2.33 ml, 14.5 mmol) was added. The reaction was heated at reflux for an hour and cooled. A waxy solid formed. The reaction mixture was partitioned between ethyl acetate (600 mL) and water (1 L), and the aqueous layer was extracted with ethyl acetate. The combined organic layers were washed with brine, dried, and concentrated. The solids were triturated with ether (150 mL) for an hour and filtered to afford 3-methylpyridine-2-thiol (5.69 g, 45.5 mmol, 31.3 % yield) as a yellow powder.
• Step B To a solution of 2-methylpyridin-3-ol (11.8 g, 108 mmol) in DMF at 0 °C was added sodium hydride (60% dispersion in oil, 4.32 g, 108 mmol) in small portions and the reaction was warmed to ambient temperature. To this mixture was added 5-bromo-3-nitropicolinonitrile (24.6 g, 108 mmol) and the reaction was stirred overnight at ambient temperature. The reaction was poured into water (1000 mL) and the aqueous layer extracted with EtOAc. The combined organic layers were washed with water and brine, dried over MgSO 4 and concentrated in vacuo to yield 5-bromo-3-(2-methylpyridin-3-yloxy)picolinonitrile (15 g, 48%).
• sodium hydride 50% dispersion in oil, 4.32 g, 108 mmol
• Step C 3-Methylpyridine-2(1H)-thione (0.906 g, 7.24 mmol) and 5-bromo-3-(2-methylpyridin-3-yloxy)picolinonitrile (2.00 g, 6.89 mmol) were dissolved in DMF (12 mL) and the mixture was cooled to 0 °C. Sodium hydride (95%; 0.183 g, 7.24 mmol) was slowly added and the reaction was warmed to ambient temperature and stirred overnight. The reaction mixture was poured into water (100 mL), stirred for 30 minutes, then filtered to afford a solid which was purified over silica gel (2:3 hexanes:ethyl acetate).
• Step D Concentrated sulfuric acid (8 mL) was added to 5-(3-methylpyridin-2-ylthio)-3-(2-methylpyridin-3-yloxy)picolinonitrile (1.40 g, 4.19 mmol). The reaction was stirred over the weekend, then poured onto ice (100 g), cooled in an ice bath and made basic to pH 10 with 50% NaOH.
• reaction mixture was extracted with ethyl acetate, washed with brine, dried (MgSO 4 ), and concentrated to afford 5-(3-methylpyridin-2-ylthio)-3-(2-methylpyridin-3-yloxy)picolinamide (1.40 g, 3.97 mmol, 94.9 % yield) as a colorless oil which became a white crystalline solid overnight under vacuo.
• Step E To a solution of 2N sodium hydroxide (8.94 ml, 17.9 mmol) at 0 °C was added bromine (0.825 g, 5.16 mmol) in one portion. The reaction was stirred for 15 minutes and a solution of 5-(3-methylpyridin-2-ylthio)-3-(2-methylpyridin-3-yloxy)picolinamide (1.40 g, 3.97 mmol) in dioxane (30 mL) was added. The reaction was stirred at ambient temperature for one hour, and then at 80 °C for an additional hour. The reaction was cooled, then stirred overnight at ambient temperature. Concentrated HCI was added to adjust the reaction mixture to about pH 2, and the mixture was stirred about 20 minutes until carbon dioxide formation stopped.
• Step F To 1000 mL of DI water was added hydroxyl amine hydrochloride (51.0 g, 734 mmol) and the mixture was stirred for 5 minutes. Sodium carbonate (38.1 g, 360 mmol) was added in 3 large portions and the reaction was stirred for 15 minutes. THF (700 mL) was added to the reaction and (R)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde (125 g, 734 mmol) in 800 mL of THF was added in 1 portion. The reaction was stirred for 4 hours and poured into a 4 L separatory funnel and the layers were separated. The aqueous layer was extracted twice with MTBE (about 3000 mL total).
• Step G To a 4-neck 2 L round bottom flask was added (S)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde oxime (135.1 g, 729.4 mmol) dissolved in 750 mL of DMF. The reaction was placed in a water bath and 1-chloropyrrolidine-2,5-dione (97.40 g, 729.4 mmol) was added in portions over 2 minutes. The reaction was stirred in a water bath for 3 hours, then diluted with 2L of MTBE and washed with 1L of water. The water was extracted with 500 mL of MTBE.
• Step H To a 4 neck 5 L flask was added (R)-N-hydroxy-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (158 g, 719 mmol) in 2.5 L of THF. The material was cooled to 3 °C and methanesulfonyl chloride (56.1 ml, 719 mmol) was added in 10 mL portions over 10 minutes. N-ethyl-N-isopropylpropan-2-amine (126 ml, 719 mmol) was added through an addition funnel over 12 minutes. The reaction was stirred in the ice bath for 30 minutes and then at ambient temperature for 1 hour.
• Step I To acetonitrile (50 mL) was added sodium isothiocyanate (0.1749 g, 2.158 mmol), pyridine (0.3740 ml, 4.624 mmol), followed by (R)-N-(methylsulfonyloxy)-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (0.5507 g, 1.850 mmol), and the resulting mixture was heated to 60 °C for 30 minutes.
• Step J To a solution of (S)-N-(5-(3-methylpyridin-2-ylthio)-3-(2-methylpyridin-3-yloxy)pyridin-2-yl)-3-(1,4-dioxaspiro[4.5]decan-2-yl)-1,2,4-thiadiazol-5-amine (0.565 g, 1.03 mmol) in ethanol (25 mL) was added an aqueous solution of 6N HCI (2 mL). The reaction was heated at 80 °C for 2 hours, cooled to ambient temperature, stirred for 30 minutes, then cooled at 0 °C for an hour.
• Step A A flask was charged with 2,4-dimethylpyridin-3-ol (9.0 g, 73.1 mmol) and DMF (80 mL) was added. Sodium hydride (2.03 g, 80.4 mmol) was added and the reaction was stirred for 15 minutes. 5-Bromo-3-nitropicolinonitrile (16.7 g, 73.1 mmol) was added and the reaction was stirred for 25 minutes.
• reaction mixture was poured into 600 mL saturated NH 4 Cl and 600 mL water and then filtered, washed with water and a small amount of hexanes, and dried over high vacuum to provide 5-bromo-3-(2,4-dimethylpyridin-3-yloxy)picolinonitrile (20.5 g, 67.4 mmol, 92.2 % yield) as a light tan solid.
• Step B Pyridine-2(1H)-thione (0.768 g, 6.90 mmol) and 5-bromo-3-(2,4-dimethylpyridin-3-yloxy)picolinonitrile (2.00 g, 6.58 mmol) were added to DMF (12 mL) and cooled to 0 °C. 95% Sodium hydride (0.174 g, 6.90 mmol) was slowly added and the reaction was warmed to ambient temperature and stirred overnight. The reaction mixture was poured into water (100 mL) and stirred for 30 minutes. A cloudy milky solution that was not filterable resulted. The reaction was extracted twice with ethyl acetate. The combined organic layers were washed twice with water and brine, dried, and concentrated.
• Step C Concentrated sulfuric acid (8 mL) was added to 3-(2,4-dimethylpyridin-3-yloxy)-5-(pyridin-2-ylthio)picolinonitrile (2.03 g, 6.07 mmol). The reaction was stirred overnight, then poured onto ice (100 g), cooled in an ice bath and made basic to pH 10 with 50% NaOH. The reaction was extracted with ethyl acetate, washed with brine, dried (MgSO 4 ), and concentrated to afford 3-(2,4-dimethylpyridin-3-yloxy)-5-(pyridin-2-ylthio)picolinamide (2.02 g, 5.73 mmol, 94.4 % yield) as a white solid.
• Step D To a solution of 2N sodium hydroxide (12.9 ml, 25.8 mmol) at 0 °C was added bromine (1.19 g, 7.45 mmol) in one portion. The reaction was stirred 15 minutes, then a solution of 3-(2,4-dimethylpyridin-3-yloxy)-5-(pyridin-2-ylthio)picolinamide (2.02 g, 5.73 mmol) in dioxane (30 mL) was added. The reaction was stirred at ambient temperature for one hour, at 80 °C for an additional hour, then overnight at ambient temperature. Concentrated hydrochloric was added to adjust the mixture to about pH 2. The reaction was stirred for 20 minutes until CO 2 formation subsided and the reaction was homogenous.
• Step E In 1000 mL of DI water was added hydroxyl amine hydrochloride (51.0 g, 734 mmol) and the reaction was stirred for 5 minutes. Sodium carbonate (38.1 g, 360 mmol) was added in 3 large portions and the reaction was stirred for 15 minutes. THF (700 mL) was added to the reaction and (R)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde (125 g, 734 mmol) was added in 1 portion in 800 mL of THF. The reaction was stirred for 4 hours and poured into a 4 L separatory funnel and the layers separated. The aqueous layer was extracted twice with MTBE (about 3000 mL total).
• Step F To a 4-neck 2 L round bottom flask was added (S)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde oxime (135.1 g, 729.4 mmol) and 750 mL of DMF. The reaction was placed in a water bath and 1-chloropyrrolidine-2,5-dione (97.40 g, 729.4 mmol) was added in portions over 2 minutes. The reaction was stirred in the water bath for 3 hours, then diluted with 2L of MTBE and washed with 1 L of water. The water was extracted with 500 mL of MTBE.
• Step G To a 4 neck 5 L flask was added (R)-N-hydroxy-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (158 g, 719 mmol) in 2.5 L of THF. The material was cooled to 3 °C and methanesulfonyl chloride (56.1 ml, 719 mmol) added in 10 mL portions over 10 minutes. N-ethyl-N-isopropylpropan-2-amine (126 ml, 719 mmol) was added through an addition funnel over 12 minutes. The reaction was stirred in the ice bath for 30 minutes and then at ambient temperature for 1 hour.
• Step H To acetonitrile (50 mL) was added sodium isothiocyanate (0.1469 g, 1.813 mmol), pyridine (0.3141 ml, 3.884 mmol), followed by (R)-N-(methylsulfonyloxy)-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (0.4626 g, 1.554 mmol) and the resulting mixture was heated to 60 °C for 30 minutes.
• Step I To a solution of (S)-N-(3-(2,4-dimethylpyridin-3-yloxy)-5-(pyridin-2-ylthio)pyridin-2-yl)-3-(1,4-dioxaspiro[4.5]decan-2-yl)-1,2,4-thiadiazol-5-amine (0.360 g, 0.656 mmol) in ethanol (25 mL) was added an aqueous 6N solution of HCI (2 mL). The reaction was heated at 80 °C for 2 hours, then cooled to ambient temperature, stirred for 30 minutes, then cooled to 0 °C. Ether (25 mL) was slowly added to initiate precipitation/crystallization.
• Step A To 600 mL of DMF in a 4 neck 3000 mL round bottom flask equipped with an overhead stir mechanism under nitrogen was added 2-methylpyridin-3-ol (71.8 g, 658 mmol), and the reaction was cooled to 2 °C. 60% sodium hydride (26.3 g, 658 mmol) was added over 30 minutes while maintaining the internal temperature below 10 °C. The reaction was stirred while warming to ambient temperature for 1 hour. To the reaction was added 5-bromo-3-nitropicolinonitrile (150 g, 658 mmol) in a solution of 400 mL of DMF in two portions and the reaction held at ambient temperature for 1.5 hours.
• Step B To concentrated H 2 SO 4 (90 mL) cooled with an ice bath was added 3-(2-methylpyridin-3-yloxy)-5-(pyridin-2-ylthio)picolinonitrile (43 g, 130 mmol) in portions such that the internal temperature did not exceed 50 °C but did not go below 25 °C. After complete addition, the mixture was stirred in the ice bath until the reaction started to cool, at which point the reaction was removed from the ice bath and the mixture was heated to 50 °C. The reaction was cooled to ambient temperature and slowly added to ice water over 3 minutes (about 1400 mL of 30% ice in water). The mixture was further cooled in an ice bath to 5 °C.
• the mixture was neutralized to pH ⁇ 10 with 4M NaOH (about 800 mL) such that the internal temperature did not exceed 20 °C, at which point a solid formed.
• the mixture was stirred for 20 minutes, then filtered and washed with MTBE (5 x 150 mL), hexanes (5 x 100 mL), and dried at under vacuum to afford 3-(2-methylpyridin-3-yloxy)-5-(pyridin-2-ylthio)picolinamide (43 g, 96%).
• Step C To a 3-neck 2 L round bottom flask was added 2M aqueous sodium hydroxide (343 ml, 686 mmol) and the solution was cooled in an ice bath. Bromine (12 ml, 257 mmol) was added and the reaction was stirred for 30 minutes while the ice bath was removed. 3-(2-Methylpyridin-3-yloxy)-5-(pyridin-2-ylthio)picolinamide (58 g, 171 mmol) was added as a slurry in about 600 mL of dioxanes in 1 portion. After 30 minutes, concentrated HCI was added in 1 mL portions to about pH 1. The reaction was stirred for 15 minutes and 4N NaOH was added to the solution to about pH 10.
• 2M aqueous sodium hydroxide 343 ml, 686 mmol
• Step D (R)-2,2,5,5-Tetramethyl-1,3-dioxolane-4-carbaldehyde (16 g, 101 mmol) [ Burger, A. Synthesis 1989, (2) 93-97 ] was dissolved in 1:1 methanol:water (250 mL) and hydroxylamine hydrochloride (7.0 g, 101 mmol), and Na 2 CO 3 (5.4 g, 51 mmol) was added. The reaction was stirred at ambient temperature for 2 hours.
• Step E (S)-2,2,5,5-tetramethyl-1,3-dioxolane-4-carbaldehyde oxime (13 g, 75.1 mmol) was dissolved in DMF (200 mL) and cooled in an ice bath. 1-Chloropyrrolidine-2,5-dione (10.0 g, 75.1 mmol) was added and the reaction was stirred overnight while slowly warming to ambient temperature. The pale yellow solution was poured into water (1.5 L) and extracted with EtOAc. The organic layers were washed with water and brine, dried, filtered and concentrated.
• Step F (R)-N-hydroxy-2,2,5,5-tetramethyl-1,3-dioxolane-4-carbimidoyl chloride (12.4 g, 59.7 mmol) was dissolved in Et 2 O (200 mL) and cooled in an ice bath. Methanesulfonyl chloride (4.6 ml, 59.7 mmol) was added. Triethylamine (8.3 ml, 59.7 mmol) was added slowly and the reaction was stirred in an ice bath for 30 minutes. The reaction was filtered and concentrated.
• Step G (R)-2,2,5,5-Tetramethyl-N-(methylsulfonyloxy)-1,3-dioxolane-4-carbimidoyl chloride (138 mg, 0.483 mmol) was dissolved in CH 3 CN (3 mL). NaNCS (39.2 mg, 0.483 mmol) and pyridine (104 ⁇ L, 1.29 mmol) were added, and the reaction was heated to 45 °C for 45 minutes. 3-(2-Methylpyridin-3-yloxy)-5-(pyridin-2-ylthio)pyridin-2-amine (100 mg, 0.322 mmol) was added, and the reaction was heated to 65 °C overnight.
• Step H (S)-N-(3-(2-methylpyridin-3-yloxy)-5-(pyridin-2-ylthio)pyridin-2-yl)-3-(2,2,5,5-tetramethyl-1,3-dioxolan-4-yl)-1,2,4-thiadiazol-5-amine (145 mg, 0.2774 mmol) was dissolved in EtOH (5 mL), and 6M HCI (0.3 mL) was added. The reaction was stirred at ambient temperature for 2 hours and then at 70 °C for 2 hours. The reaction was cooled to ambient temperature and partitioned between CH 2 Cl 2 and saturated aqueous sodium bicarbonate.
• Step A To a solution of 2-methylpyridin-3-ol (11.8 g, 108 mmol) in DMF at 0 °C was added sodium hydride (60% dispersion in oil, 4.32 g, 108 mmol) in small portions and the reaction was warmed to ambient temperature. 5-Bromo-3-nitropicolinonitrile (24.6 g, 108 mmol) was added and the reaction was stirred overnight at ambient temperature. The reaction was poured into water (1000 mL) and the aqueous layer extracted with EtOAc. The combined organic layers were washed with water and brine, dried over MgSO 4 and concentrated in vacuo to yield 5-bromo-3-(2-methylpyridin-3-yloxy)picolinonitrile (15 g, 48%).
• sodium hydride 50% dispersion in oil, 4.32 g, 108 mmol
• Step B To 5-bromo-3-(2-methylpyridin-3-yloxy)picolinonitrile (15 g, 52 mmol) was added concentrated H 2 SO 4 (30 mL) and the slurry was stirred overnight, at which point the material was fully dissolved. The reaction was poured into 0 °C water in small portions. While maintaining the temp below 20 °C, the aqueous layer was basified by the addition of NaOH pellets, to a pH of about 5, at which point a solid formed. The solid was filtered, and the remaining aqueous layer was extracted with EtOAc. The organic layers, combined with the solid, were washed with brine, dried over MgSO 4 and concentrated in vacuo to yield 5-bromo-3-(2-methylpyridin-3-yloxy)picolinamide (11g, 69%).
• Step C To a solution of NaOH (2M, 90 mL, 182 mmol) at 0 °C was added bromine (8.71 g, 54 mmol) and the reaction was stirred at 0 °C for 30 minutes.
• the reaction was cooled to ambient temperature and acidified to pH 1 using concentrated HCl.
• the reaction was basified and a solid precipitated. The solid was filtered and dried in vacuo to yield product 5-bromo-3-(2-methylpyridin-3-yloxy)pyridin-2-amine (4.1 g, 41%).
• Step D In 1000 mL of DI water was added hydroxyl amine hydrochloride (51.0 g, 734 mmol) and the reaction was stirred for 5 minutes. Sodium carbonate (38.1 g, 360 mmol) was added in 3 large portions and the reaction was stirred for 15 minutes. THF (700 mL) was added to the reaction and (R)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde (125 g, 734 mmol) was added in 1 portion in 800 mL of THF. The reaction was stirred for 4 hours and poured into a 4 L separatory funnel and the layers separated. The aqueous layer was extracted twice with MTBE (3000 mL total).
• Step E To a 4-neck 2 L round bottom flask was added (S)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde oxime (135.1 g, 729.4 mmol) and dissolved in 750 mL of DMF. The reaction was placed in a water bath and 1-chloropyrrolidine-2,5-dione (97.40 g, 729.4 mmol) was added in portions over 2 minutes. The reaction was stirred in the water bath for 3 hours, then diluted with 2L of MTBE and washed with 1L of water. The aqueous layer was extracted with 500 mL of MTBE.
• Step F In a 4 neck 5 L flask was added (R)-N-hydroxy-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (158 g, 719 mmol) in 2.5 L of THF. The material was cooled to 3 °C and methanesulfonyl chloride (56.1 ml, 719 mmol) added in 10 mL portions over 10 minutes. N-ethyl-N-isopropylpropan-2-amine (126 ml, 719 mmol) was added through an addition funnel over 12 minutes. The reaction was stirred in an ice bath for 30 minutes and then at ambient temperature for 1 hour.
• Step G In 100 mL of acetonitrile was added sodium thioisocyanate (1.5 g, 20 mmol), pyridine (3.5g, 44 mmol), followed by (R)-N-(methylsulfonyloxy)-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (5.2g, 18 mmol) and the reaction heated to 60 °C for 30 minutes. 5-Bromo-3-(2-methylpyridin-3-yloxy)pyridin-2-amine (4.1g, 15 mmol) was added and the reaction was heated overnight at 60 °C. The reaction was concentrated to one quarter volume and the residue was partitioned between EtOAc and water made basic with 1 N NaOH.
• Step H To a solution of (S)-N-(5-bromo-3-(2-methylpyridin-3-yloxy)pyridin-2-yl)-3-(1,4-dioxaspiro[4.5]decan-2-yl)-1,2,4-thiadiazol-5-amine (3.1g, 6.14 mmol) in dioxanes (30 mL) continuously purged with nitrogen was added Xanphos (0.177g, 0.303 mmol), Pd 2 dba 3 (0.14 g, 0.153 mmol), methyl 3-mercaptopropanoate (0.73 g, 6.14 mmol) and N,N-diisopropylethylamine (1.17 mL, 6.45 mmol) and the reaction was heated overnight at 80 °C.
• Step I (S)-Methyl 3-(6-(3-(1,4-dioxaspiro[4.5]decan-2-yl)-1,2,4-thiadiazol-5-ylamino)-5-(2-methylpyridin-3-yloxy)pyridin-3-ylthio)propanoate (2.0 g, 3.68 mmol) was dissolved in THF (20 mL) and nitrogen was bubbled through the solution for 5 minutes. Potassium 2-methylpropan-2-olate (1M in THF, 11.0 ml, 11.0 mmol) was added and the reaction was stirred at ambient temperature for 1 minute.
• Step J (S)-N-(5-(2-methoxyethylthio)-3-(2-methylpyridin-3-yloxy)pyridin-2-yl)-3-(1,4-dioxaspiro[4.5]decan-2-yl)-1,2,4-thiadiazol-5-amine (1.9 g, 3.68 mmol) was dissolved in EtOH (50 mL) and 6M HCl (3 mL) added and heated to 60 °C for 1.5 hours. The reaction was cooled to ambient temperature and partitioned between CH 2 Cl 2 and saturated aqueous sodium bicarbonate, extracted with CH 2 Cl 2 , dried, filtered and concentrated.
• Step A 2-Bromopyridin-3-yl acetate (10 g, 46 mmol) was dissolved in THF (80 mL) and triethylamine (32 ml, 231mmol), ethynyltrimethylsilane (19.5 ml, 139 mmol), and Cul (0.44 g, 2.3 mmol) were added. The mixture was degassed with argon for 15 minutes. PdCl 2 (PPh 3 ) 2 (1.6 g, 2.3 mmol) was added and the mixture stirred under argon at ambient temperature for 18 hours.
• PdCl 2 (PPh 3 ) 2 1.6 g, 2.3 mmol
• Step B To a solution of 2-((trimethylsilyl)ethynyl)pyridin-3-yl acetate (9.5 g, 41 mmol) in THF (200 mL) was added water (25 ml). The reaction was cooled to 0 °C and TBAF (1 M, 45 ml, 45 mmol) was added. The mixture warmed to ambient temperature and stirred for 1 hour. Water (100 mL) was added and the volume was reduced by half. The product was extracted into ether (3 x 100 mL), washed with brine and dried over MgSO 4 . The solution was concentrated in vacuo to afford 2-ethynylpyridin-3-yl acetate (5.5 g, 34 mmol) as a light brown oil.
• Step C To a solution of 2-ethynylpyridin-3-yl acetate (5.0 g, 31 mmol) in ethanol (50 mL) was added PtO 2 (0.50 g, 2.2 mmol). The mixture was degassed with nitrogen and placed under a double-layer balloon of hydrogen. The reaction was stirred at ambient temperature for 30 minutes. The mixture was filtered and concentrated in vacuo to give 2-ethylpyridin-3-yl acetate (5.1 g, 31 mmol) that was used without further purification.
• Step D To a solution of 2-ethylpyridin-3-yl acetate (5.1 g, 31 mmol) in ethanol (50 mL) was added 3M LiOH (50 mL, 150 mmol). The reaction mixture stirred at ambient temperature for 30 minutes. The mixture was concentrated to dryness and purified over silica gel (10% MeOH in CH 2 Cl 2 ) to afford 2-ethylpyridin-3-ol (2.5 g, 20 mmol).
• Step E 2-Ethylpyridin-3-ol (27.5 g, 223 mmol) was dissolved in DMF (900 mL) and cooled in an ice bath. 60% Sodium hydride (8.93 g, 223 mmol) was added portionwise and stirred in an ice bath for 30 minutes. 5-Bromo-3-nitropicolinonitrile (50.9 g, 223 mmol) was added in one portion and the reaction was stirred in an ice bath for 1 hour. Pyridine-2(1H)-thione (24.8 g, 223 mmol) was added, followed by 60% sodium hydride (8.93 g, 223 mmol) and reaction was stirred in an ice bath slowly warming to ambient temperature overnight.
• Step F 3-(2-Ethylpyridin-3-yloxy)-5-(pyridin-2-ylthio)picolinonitrile (80 g, 239 mmol) was cooled in an ice/acetone bath. 12M Hydrogen chloride (598 ml, 7177 mmol) was chilled in an ice/acetone bath and then added slowly to the oil in the flask. After agitating for 40 minutes all the starting material dissolved and the bath was removed and the mixture was stirred at ambient temperature over the weekend. The reaction was cooled in an ice bath and 6N NaOH (1200 mL) was added slowly while keeping the temperature below 20 °C to a final pH of about 9.
• Step G 3-(2-Ethylpyridin-3-yloxy)-5-(pyridin-2-ylthio)picolinamide (71 g, 201 mmol) was dissolved in MeOH (1 L).
• 1-Bromopyrrolidine-2,5-dione (46.6 g, 262 mmol) was added and the reaction was stirred at ambient temperature for 5 minutes and then cooled in an ice bath.
• Sodium hydroxide (41.9 g, 1048 mmol) dissolved in water (200 mL) was added slowly and the reaction was stirred at ambient temperature for 1 hour, refluxed for 8 hours and then cooled to ambient temperature overnight. The reaction was diluted with 2.5 L water and 0.5 L NH 4 Cl and stirred for 30 minutes.
• Step H (2R,3R)-diethyl 2,3-dihydroxysuccinate (82.99 ml, 485.0 mmol) was dissolved in Toluene (400 mL) and cyclohexanone (55.29 ml, 533.5 mmol) and Amberlyst 15 ion-exchange resin (2.0 g) were added and the reaction refluxed under dean stark trap for 12 hours. The reaction was cooled to ambient temperature, filtered and concentrated.
• Step I (2R,3R)-diethyl 1,4-dioxaspiro[4.5]decane-2,3-dicarboxylate (91.3 g, 319 mmol) was dissolved in THF (1.5 L) and cooled in ice bath. 2M LAH (120 ml, 239 mmol) was added slowly and the reaction stirred at 0 °C. Small aliquots were taken and 1 H NMR analyzed for completion of reaction. Sodium sulfate decahydrate was added slowly, and allowed to stir at ambient temperature for 1 hour. The reaction was filtered through celite and concentrated to afford batch 1 (45.3 g). The celite was stirred in EtOAc for 30 min and filtered again to afford batch 2 (9.8 g).
• Step J (2S,3S)-1,4-dioxaspiro[4.5]decane-2,3-diyldimethanol (65 g, 321.4 mmol) was dissolved in DMF (500 mL) and cooled in an ice bath. 60% Sodium hydride (15.43 g, 385.7 mmol) was added slowly and the reaction was stirred for 30 minutes in an ice bath then warmed to ambient temperature for 2 hours. lodomethane (20.05 ml, 321.4 mmol) was added and the reaction was stirred at ambient temperature overnight. The majority of the DMF was removed on a rotary evaporator, and the residue was partitioned between aqueous NH 4 Cl and EtOAc.
• Step K A solution of methylsulfinylmethane (20.6 ml, 289 mmol) in CH 2 Cl 2 (260 mL) at -60 °C, was added dropwise to a 2M solution of oxalyl dichloride (15.2 ml, 174 mmol) in CH 2 Cl 2 (80 mL). The mixture was stirred for 20 minutes and then a solution of ((2S,3S)-3-(methoxymethyl)-1,4-dioxaspiro[4.5]decan-2-yl)methanol (31.3 g, 145 mmol) in CH 2 Cl 2 (80 mL) was added dropwise.
• Step L Crude (2R,3S)-3-(methoxymethyl)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde (31 g, 145 mmol) was dissolved in 1:1 methanol:water (600 mL), and hydroxylamine hydrochloride (10.1 g, 145 mmol) and Na 2 CO 3 (7.67 g, 72.3 mmol) were added. The reaction was stirred at ambient temperature for 3 hours.
• Step M 3-(Methoxymethyl)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde oxime (33.2 g, 145 mmol) was dissolved in DMF (600 mL) and cooled in an ice bath. 1-Chloropyrrolidine-2,5-dione (19.3 g, 145 mmol) was added and the reaction allowed to slowly warm to ambient temperature overnight. Most of the DMF was removed under reduced pressure and the remaining material was partitioned between water and EtOAc.
• Step N (2R,3S)-N-hydroxy-3-(methoxymethyl)-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (35.6 g, 135.0 mmol) was dissolved in Et 2 O (600 mL) and cooled in an ice bath. Methanesulfonyl chloride (10.49 ml, 135.0 mmol) was added, followed by dropwise addition of triethylamine (18.82 ml, 135.0 mmol). The reaction was stirred for 30 minutes and then filtered and concentrated.
• Step O (2R,3S)-3-(Methoxymethyl)-N-(methylsulfonyloxy)-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (2.29 g, 6.70 mmol) was dissolved in EtOAc (40 mL), and NaNCS (0.544 g, 6.70 mmol) and pyridine (1.44 ml, 17.9 mmol) were added and the reaction was heated to 45 °C for 45 minutes.
• Step P N-(3-(2-ethylpyridin-3-yloxy)-5-(pyridin-2-ylthio)pyridin-2-yl)-3-((2S,3S)-3-(methoxymethyl)-1,4-dioxaspiro[4.5]decan-2-yl)-1,2,4-thiadiazol-5-amine (1.6 g, 2.70 mmol) was dissolved in EtOH (30 mL) and 4N HCl (1 mL) added and heated to 50 °C overnight. Additional 4N HCl was added (1 mL) and heated for 4 hours.
• Step A A flask was charged with powdered potassium hydroxide (21.89 g, 390.2 mmol), benzoic acid (47.65 g, 390.2 mmol), and DMF (500 mL) was added. The mixture was heated at 50 °C for 1 hour. 3-Chloropentane-2,4-dione (52.5 g, 390.2 mmol) was added and the reaction was stirred at 50 °C overnight. The reaction was cooled to ambient temperature, diluted in water (1.5 L) and extracted with ether (3 x 500 mL). The combined organic layers were washed with water, saturated NH 4 Cl and brine. The organic layer was dried over sodium sulfate and concentrated in vacuo to afford 2,4-dioxopentan-3-yl benzoate (82.59 g, 96.12 % yield) as a yellow oil.
• Step B A flask was charged with 2,4-dioxopentan-3-yl benzoate (82.59 g, 375.0 mmol) and ethanol (1.5 L) was added. Methylhydrazine (39.90 ml, 750.1 mmol) in ethanol (150 mL) was added, and the reaction was stirred at ambient temperature for 2 hours, then concentrated in vacuo to afford 1,3,5-trimethyl-1H-pyrazol-4-yl benzoate (80 g, 92.6% yield).
• Step C A flask was charged with 1,3,5-trimethyl-1H-pyrazol-4-yl benzoate (80 g, 347 mmol), and added 500 mL ethanol. 3M NaOH (174 ml, 521 mmol) was added and the reaction was stirred at ambient temperature for 2 hours. The ethanol was removed in vacuo and the aqueous layer was extracted with dichloromethane, ethyl acetate and dichloromethane:isopropyl alcohol (4:1). The combined organic layers were dried over sodium sulfate, filtered and concentrated in vacuo to afford 1,3,5-trimethyl-1H-pyrazol-4-ol (34 g, 78 % yield) as white solid.
• Step D A flask was charged with 1,3,5-trimethyl-1H-pyrazol-4-ol (10.46 g, 82.89 mmol), and DMF:dioxane (9:1) (700 mL). The reaction mixture was cooled to 0 °C and 60% sodium hydride (3.315 g, 82.89 mmol) was added portionwise. The reaction mixture was stirred for 15 minutes, and 5-bromo-3-nitropicolinonitrile (18 g, 78.95 mmol) was added. The reaction was stirred at ambient temperature for 3 hours, then poured slowly into 600 mL water and stirred for 10 minutes.
• Step E A flask was charged with 5-bromo-3-(1,3,5-trimethyl-1H-pyrazol-4-yloxy)picolinonitrile (27.77 g, 90.41 mmol), pyridine-2-thiol (10.55 g, 94.93 mmol), and DMF (300 mL). The reaction was cooled to 0 °C and 95% sodium hydride (2.741 g, 108.5 mmol) was added portionwise. The reaction was stirred at ambient temperature overnight, then carefully diluted with water (2 L) and extracted with ethyl acetate.
• Step F A flask was charged with 5-(pyridin-2-ylthio)-3-(1,3,5-trimethyl-1H-pyrazol-4-yloxy)picolinonitrile (35.19 g, 88.1 mmol), and sulfuric acid (227.3 g, 2317 mmol) and stirred at ambient temperature overnight. Water (100 mL) was added very slowly to the reaction which was cooled in an ice bath, and then150 g of ice was added. NaOH (40%) was slowly added until pH was adjusted to about12. The mixture was extracted ethyl acetate (750 mL x 2), and dichloromethane (500 mL).
• Step G A flask was charged with potassium hydroxide (78.8 ml, 236 mmol), bromine (4.04 ml, 78.8 mmol) was added and the reaction was stirred at ambient temperature for 15 minutes.
• 5-(Pyridin-2-ylthio)-3-(1,3,5-trimethyl-1H-pyrazol-4-yloxy)picolinamide (14 g, 39.4 mmol) in dioxane (280 mL) was added and the reaction was stirred at ambient temperature overnight.
• Water (300 mL) was added and the reaction was extracted with ethyl acetate. The organic layer was dried over sodium sulfate, filtered and concentrated.
• Step H (R)-2,2,5,5-Tetramethyl-1,3-dioxolane-4-carbaldehyde (16 g, 101 mmol) [ Burger, A. Synthesis 1989, (2) 93-97 ] was dissolved in 1:1 methanol:water (250 mL). Hydroxylamine hydrochloride (7.0 g, 101 mmol) and Na 2 CO 3 (5.4 g, 51 mmol) were added and the reaction was stirred at ambient temperature for 2 hours.
• Step I (S)-2,2,5,5-tetramethyl-1,3-dioxolane-4-carbaldehyde oxime (13 g, 75.1 mmol) was dissolved in DMF (200 mL) and cooled in an ice bath. 1-Chloropyrrolidine-2,5-dione (10.0 g, 75.1 mmol) was added and the reaction was stirred overnight, slowly warming to ambient temperature. The pale yellow solution was poured into water (1.5 L) and extracted with EtOAc. The combined organic layers were washed with water and brine, dried, filtered and concentrated.
• Step J (R)-N-hydroxy-2,2,5,5-tetramethyl-1,3-dioxolane-4-carbimidoyl chloride (12.4 g, 59.7 mmol) was dissolved in Et 2 O (200 mL) and cooled in an ice bath. Methanesulfonyl chloride (4.6 ml, 59.7 mmol) was added. Triethylamine (8.3 ml, 59.7 mmol) was added slowly and the reaction was stirred in an ice bath for 30 minutes. The reaction was filtered and concentrated.
• Step K A flask was charged with (R)-2,2,5,5-tetramethyl-N-(methylsulfonyloxy)-1,3-dioxolane-4-carbimidoyl chloride (0.371 g, 1.30 mmol), sodium thiocyanate (0.0929 g, 1.15 mmol), pyridine (0.278 ml, 3.44 mmol), and acetonitrile (25 mL) and the reaction was heated to 40 °C for 30 minutes.
• Step L A flask was charged with (S)-N-(5-(pyridin-2-ylthio)-3-(1,3,5-trimethyl-1H-pyrazol-4-yloxy)pyridin-2-yl)-3-(2,2,5,5-tetramethyl-1,3-dioxolan-4-yl)-1,2,4-thiadiazol-5-amine (0.233 g, 0.432 mmol), ethanol (10 mL), and 3M HCl (0.288 ml, 0.863 mmol). The reaction was heated to 75 °C for 1 hour and then concentrated in vacuo. Ether was added to the residue and the mixture was stirred for 2 minutes to precipitate the product.
• Step A A flask was charged with powdered potassium hydroxide (21.89 g, 390.2 mmol), benzoic acid (47.65 g, 390.2 mmol), and DMF (500 mL). The mixture was heated at 50 °C for 1 hour. 3-Chloropentane-2,4-dione (52.5 g, 390.2 mmol) was added and the reaction was stirred at 50 °C overnight. The reaction was cooled to ambient temperature, diluted in water (1.5 L) and extracted with ether (3 x 500 mL). The combined organic layers were washed with water, saturated NH 4 Cl and brine. The organic layer was dried over sodium sulfate and concentrated in vacuo to afford 2,4-dioxopentan-3-yl benzoate (82.59 g, 96.12 % yield) as yellow oil.
• Step B A flask was charged with 2,4-dioxopentan-3-yl benzoate (82.59 g, 375.0 mmol) and ethanol (1.5 L) was added. To this solution was added methylhydrazine (39.90 ml, 750.1 mmol) in ethanol (150 mL). The reaction was stirred at ambient temperature for 2 hours and concentrated in vacuo to afford 1,3,5-trimethyl-1H-pyrazol-4-yl benzoate (80 g, 92.6% yield).
• Step C A flask was charged with 1,3,5-trimethyl-1H-pyrazol-4-yl benzoate (80 g, 347 mmol), and 500 mL ethanol was added. 3M NaOH (174 ml, 521 mmol) was added and the reaction was stirred at ambient temperature for 2 hours. The ethanol was removed in vacuo and the aqueous layer was extracted with dichloromethane, ethyl acetate and dichloromethane:isopropyl alcohol (4:1). The combined organic layers were dried over sodium sulfate, filtered and concentrated in vacuo to afford 1,3,5-trimethyl-1H-pyrazol-4-ol (34 g, 78 % yield) as white solid.
• Step D A flask was charged with 1,3,5-trimethyl-1H-pyrazol-4-ol (10.46 g, 82.89 mmol), and added DMF:dioxane (9:1) (700 mL). The reaction mixture was cooled to 0 °C and 60% sodium hydride (3.315 g, 82.89 mmol) was added portionwise and the reaction was stirred for 15 minutes. 5-Bromo-3-nitropicolinonitrile (18 g, 78.95 mmol) was added and the reaction was stirred at ambient temperature for 3 hours. The reaction was poured slowly into 600 mL water and stirred for 10 minutes.
• Step E A flask was charged with 5-bromo-3-(1,3,5-trimethyl-1H-pyrazol-4-yloxy)picolinonitrile (27.77 g, 90.41 mmol), pyridine-2-thiol (10.55 g, 94.93 mmol), and DMF (300 mL). The reaction was cooled to 0 °C and 95% sodium hydride (2.741 g, 108.5 mmol) was added portionwise. The reaction was stirred at ambient temperature overnight, then carefully diluted with water (2 L) and extracted with ethyl acetate.
• Step F A flask was charged with 5-(pyridin-2-ylthio)-3-(1,3,5-trimethyl-1H-pyrazol-4-yloxy)picolinonitrile (35.19 g, 88.1 mmol), and sulfuric acid (227.3 g, 2317 mmol) and stirred at ambient temperature overnight. Water (100 mL) was slowly added to the reaction which was cooled in an ice bath, then ice (150 g) was added. 40% NaOH was slowly added until the pH was about 12. The mixture was extracted ethyl acetate (750 mL x 2), and dichloromethane (500 mL).
• Step G A flask was charged with potassium hydroxide (78.8 ml, 236 mmol), and bromine (4.04 ml, 78.8 mmol), and the mixture was stirred at ambient temperature for 15 minutes.
• 5-(Pyridin-2-ylthio)-3-(1,3,5-trimethyl-1H-pyrazol-4-yloxy)picolinamide (14 g, 39.4 mmol) in dioxane (280 mL) was added and the reaction was stirred at ambient temperature overnight.
• Water (300 mL) was added and the mixture was extracted with ethyl acetate. The organic layer was dried over sodium sulfate, filtered and concentrated.
• Step H To 1000 mL of DI water was added hydroxyl amine hydrochloride (51.0 g, 734 mmol) and the reaction was stirred for 5 minutes. Sodium carbonate (38.1 g, 360 mmol) was added in 3 large portions and the reaction was stirred for 15 minutes. THF (700 mL) was added, followed by (R)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde (125 g, 734 mmol) in 800 mL of THF. The reaction was stirred for 4 hours, then poured into a 4 L separatory funnel. The layers were separated and the aqueous layer was extracted twice with MTBE (about 3000 mL total).
• Step I To a 4-neck 2 L round bottom flask was added (S)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde oxime (135.1 g, 729.4 mmol) and dissolved in 750 mL of DMF. The reaction was placed in a water bath and 1-chloropyrrolidine-2,5-dione (97.40 g, 729.4 mmol) was added in portions over 2 minutes. The reaction was stirred in the water bath for 3 hours. The reaction was diluted with 2L of MTBE and washed with 1L of water. The water was extracted with 500 mL of MTBE.
• Step J To a 4 neck 5 L flask was added (R)-N-hydroxy-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (158 g, 719 mmol) in 2.5 L of THF. The mixture was cooled to 3 °C, and methanesulfonyl chloride (56.1 ml, 719 mmol) was added in 10 mL portions over 10 minutes. N-ethyl-N-isopropylpropan-2-amine (126 ml, 719 mmol) was added through an addition funnel over 12 minutes. The reaction was stirred in the ice bath for 30 minutes and then at ambient temperature for 1 hour.
• Step K A flask was charged with (R)-N-(methylsulfonyloxy)-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (2.32 g, 7.79 mmol), sodium thiocyanate (0.557 g, 6.87 mmol), pyridine (1.67 ml, 20.6 mmol), and acetonitrile (100 mL).
• Step L A flask was charged with (S)-N-(5-(pyridin-2-ylthio)-3-(1,3,5-trimethyl-1H-pyrazol-4-yloxy)pyridin-2-yl)-3-(1,4-dioxaspiro[4.5]decan-2-yl)-1,2,4-thiadiazol-5-amine (1.38 g, 2.50 mmol), ethanol (50 mL), and 3M HCl (1.67 ml, 5.00 mmol) and heated to 75 °C for 1 hour. The reaction was cooled to ambient temperature, and saturated aqueous sodium bicarbonate was added slowly. The mixture was extracted with ethyl acetate and dichloromethane.
• Step A A flask was charged with powdered potassium hydroxide (21.89 g, 390.2 mmol), benzoic acid (47.65 g, 390.2 mmol), and DMF (500 mL) was added. The mixture was heated at 50 °C for 1 hour. 3-Chloropentane-2,4-dione (52.5 g, 390.2 mmol) and the reaction was stirred at 50 °C overnight. The reaction was cooled to ambient temperature, diluted in water (1.5 L) and extracted with ether (3 x 500 mL). The combined organic layers were washed with water, saturated NH 4 Cl and brine. The organic layer was dried over sodium sulfate and concentrated in vacuo to afford 2,4-dioxopentan-3-yl benzoate (82.59 g, 96.12 % yield) as yellow oil.
• Step B A flask was charged with 2,4-dioxopentan-3-yl benzoate (82.59 g, 375.0 mmol) and ethanol (1.5 L). To this solution was added methylhydrazine (39.90 ml, 750.1 mmol) in ethanol (150 mL). The reaction was stirred at ambient temperature for 2 hours and concentrated in vacuo to afford 1,3,5-trimethyl-1H-pyrazol-4-yl benzoate (80 g, 92.6% yield).
• Step C A flask was charged with 1,3,5-trimethyl-1H-pyrazol-4-yl benzoate (80 g, 347 mmol), and 500 mL ethanol. To the above mixture was added 3M NaOH (174 ml, 521 mmol) and stirred at ambient temperature for 2 hours. The ethanol was removed in vacuo and the aqueous layer was extracted with dichloromethane, ethyl acetate and dichloromethane:isopropyl alcohol (4:1). The combined organic layers were dried over sodium sulfate, filtered and concentrated in vacuo to afford 1,3,5-trimethyl-1H-pyrazol-4-ol (34 g, 78 % yield) as white solid.
• Step D A flask was charged with 1,3,5-trimethyl-1H-pyrazol-4-ol (10.46 g, 82.89 mmol), and DMF:dioxane (9:1) (700 mL). The reaction mixture was cooled to 0 °C and 60% sodium hydride (3.315 g, 82.89 mmol) was added portionwise. The reaction mixture was stirred for 15 minutes, then 5-bromo-3-nitropicolinonitrile (18 g, 78.95 mmol) was added and the reaction was stirred at ambient temperature for 3 hours. The reaction was poured slowly into 600 mL water and stirred for 10 minutes.
• Step E A flask was charged with 5-bromo-3-(1,3,5-trimethyl-1H-pyrazol-4-yloxy)picolinonitrile (7.0 g, 23 mmol) and H 2 SO 4 (56 g, 570 mmol) and the reaction was stirred at ambient temperature overnight. The reaction was cooled in an ice bath and water (100 mL) was carefully added.40% NaOH solution was slowly added till the pH was about 12.
• Step F A flask was charged with 3M KOH (45.5 ml, 137 mmol) and bromine (1.98 ml, 38.7 mmol) and the reaction was stirred for 5 minutes at ambient temperature.
• 5-Bromo-3-(1,3,5-trimethyl-1H-pyrazol-4-yloxy)picolinamide (7.4 g, 22.8 mmol) in dioxane (150 mL) was added and the reaction was stirred at ambient temperature for 6 hours. Water was added and the reaction was extracted with ethyl acetate. The combined organic layers were dried over sodium sulfate, filtered and concentrated in vacuo.
• Step G To 1000 mL of DI water was added hydroxyl amine hydrochloride (51.0 g, 734 mmol) and the mixture was stirred for 5 minutes. Sodium carbonate (38.1 g, 360 mmol) was added in 3 large portions and the reaction was stirred for 15 minutes. THF (700 mL) was added, followed by (R)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde (125 g, 734 mmol) in 800 mL of THF. The reaction was stirred for 4 hours. The layers separated and the aqueous layer was extracted twice with MTBE (about 3000 mL total).
• Step H To a 4-neck 2 L round bottom flask was added (S)-1,4-dioxaspiro[4.5]decane-2-carbaldehyde oxime (135.1 g, 729.4 mmol) and 750 mL of DMF. The reaction was placed in a water bath and 1-chloropyrrolidine-2,5-dione (97.40 g, 729.4 mmol) was added in portions over 2 minutes. The reaction was stirred in the water bath for 3 hours, then diluted with 2 L of MTBE and washed with 1 L of water. The aqueous layer was extracted with 500 mL of MTBE.
• Step I To a 4 neck 5 L flask was added (R)-N-hydroxy-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (158 g, 719 mmol) in 2.5 L of THF. The mixture was cooled to 3 °C and methanesulfonyl chloride (56.1 ml, 719 mmol) added in 10 mL portions over 10 minutes. N-ethyl-N-isopropylpropan-2-amine (126 ml, 719 mmol) was added through an addition funnel over 12 minutes. The reaction was stirred in an ice bath for 30 minutes and then at ambient temperature for 1 hour.
• Step J A flask was charged with (R)-N-(methylsulfonyloxy)-1,4-dioxaspiro[4.5]decane-2-carbimidoyl chloride (1.53 g, 5.15 mmol), pyridine (1.25 ml, 15.4 mmol), sodium thiocyanate (0.417 g, 5.15 mmol) and acetonitrile (15 mL). The solution was heated to 40 °C for 40 minutes. 5-Bromo-3-(1,3,5-trimethyl-1H-pyrazol-4-yloxy)pyridin-2-amine (1.02 g, 3.43 mmol) was added and the reaction was heated to 70 °C overnight.
• Step K A sealed tube was charged with (S)-N-(5-bromo-3-(1,3,5-trimethyl-1H-pyrazol-4-yloxy)pyridin-2-yl)-3-(1,4-dioxaspiro[4.5]decan-2-yl)-1,2,4-thiadiazol-5-amine (0.550 g, 1.055 mmol), Pd 2 (dba) 3 (0.06065 g, 0.1055 mmol), K 3 PO 4 (0.5821 g, 2.742 mmol), Xantphos (0.1221 g, 0.2110 mmol), and degassed toluene (5 mL). Nitrogen was bubbled through the solution for 5 minutes.
• Methyl 3-mercaptopropanoate (0.1752 ml, 1.582 mmol) was added and the reaction was heated to 100 °C overnight. The reaction was cooled to ambient temperature, water was added and the reaction was extracted with ethyl acetate. The organic layer was dried over sodium sulfate, filtered and concentrated in vacuo.
• Step L To a solution of (S)-methyl 3-(6-(3-(1,4-dioxaspiro[4.5]decan-2-yl)-1,2,4-thiadiazol-5-ylamino)-5-(1,3,5-trimethyl-1H-pyrazol-4-yloxy)pyridin-3-ylthio)propanoate (0.420 g, 0.749 mmol) in THF (10 mL) was added potassium 2-methylpropan-2-olate (2.36 ml, 2.36 mmol) and the reaction was stirred at ambient temperature for 5 minutes.
• Step M A flask was charged with (S)-N-(5-(2-methoxyethylthio)-3-(1,3,5-trimethyl-1H-pyrazol-4-yloxy)pyridin-2-yl)-3-(1,4-dioxaspiro[4.5]decan-2-yl)-1,2,4-thiadiazol-5-amine (0.200 g, 0.375 mmol), 3M HCl (0.751 ml, 0.751 mmol), and ethanol (5 mL). The reaction was heated to 80 °C for 1 hour and then cooled to ambient temperature.
• Step A To a solution of (S)-1-(2,2-dimethyl-1,3-dioxolan-4-yl)ethanone (10.5 g, 72.8 mmol) in 150 (mL) THF: 60 mL water was added hydroxylamine hydrochloride (5.06 g, 72.8 mmol), and the reaction was stirred for 20 minutes. Na 2 CO 3 (3.78 g, 35.7 mmol) was added and the reaction was stirred overnight.
• Step B To a solution of (R)-2,2-dimethyl-1,3-dioxolane-4-carbaldehyde oxime (10.3 g, 71.0 mmol) in 40 mL DMF was added 1-chloropyrrolidine-2,5-dione (10.4 g, 78.1 mmol) and the reaction was stirred overnight at ambient temperature. The reaction mixture was poured into ether (1400 mL) and water (500 mL).
• Step C A solution of (S)-N-hydroxy-2,2-dimethyl-1,3-dioxolane-4-carbimidoyl chloride (9.88 g, 55.01 mmol) in THF (200 mL) at 0 °C was added methanesulfonyl chloride (4.703 ml, 60.51 mmol), followed by N,N-diisopropylethylamine (10.54 ml, 60.51 mmol) and the reaction was stirred for 1 hour at ambient temperature, filtered and concentrated in vacuo.
• Step D To 600 mL of DMF in a 4 neck 3000 mL round bottom flask equipped with an overhead stir mechanism under nitrogen was added 2-methylpyridin-3-ol (71.8 g, 658 mmol) and the mixture was cooled to 2 °C. 60% Sodium hydride (26.3 g, 658 mmol) was added over 30 minutes while maintaining the internal temperature below 10 °C. The reaction was stirred while warming to ambient temperature for 1 hour. 5-Bromo-3-nitropicolinonitrile (150 g, 658 mmol) in a solution of 400 mL of DMF was added in two portions and the reaction was held at ambient temperature for 1.5 hours.
• Step E To concentrated H 2 SO 4 (90 mL) cooled with an ice bath was added 3-(2-methylpyridin-3-yloxy)-5-(pyridin-2-ylthio)picolinonitrile (43 g, 130 mmol) in portions such that the internal temp did not exceed 50 °C but did not go below 25 °C. After complete addition, the mixture was stirred in the ice bath until the reaction started to cool, at which point the reaction was removed from the ice bath and the mixture was heated to 50 °C. The reaction was cooled to ambient temperature and the mixture added to ice water slowly over 3 minutes (about 1400 mL of 30% ice in water). The mixture was further cooled in an ice bath to 5 °C.
• the mixture was neutralized to about pH 10 with 4M NaOH (about 800 mL) while maintaining the internal temperature below 20 °C, at which point a solid formed.
• the mixture was stirred for 20 minutes.
• the mixture was filtered and washed with MTBE (5 x 150 mL), hexanes (5 x 100 mL), and dried at under vacuum to afford 3-(2-methylpyridin-3-yloxy)-5-(pyridin-2-ylthio)picolinamide (43 g, 96%).
• Step F To a solution of NaOH (2M, 90 mL, 182 mmol) at 0 °C was added bromine (8.71 g, 54 mmol) and the reaction was stirred at 0 °C for 30 minutes.
• the reaction was cooled to ambient temperature and acidified to pH 1 using concentrated HCl.
• the reaction was basified and a solid precipitated. The solid was filtered and dried in vacuo to yield 5-bromo-3-(2-methylpyridin-3-yloxy)pyridin-2-amine (4.1 g, 41%).
• Step G A flask was charged with (S)-2,2-dimethyl-N-(methylsulfonyloxy)-1,3-dioxolane-4-carbimidoyl chloride (4.5 g, 18 mmol), sodium thiocyanate (1.3 g, 15 mmol), pyridine (3.8 ml, 46 mmol), and ethyl acetate (200 mL). The reaction was stirred and heated at 40 °C for 45 minutes. 3-(2-Methylpyridin-3-yloxy)-5-(pyridin-2-ylthio)pyridin-2-amine (3.2 g, 10 mmol) was added and the reaction was stirred at 70 °C overnight.
• Step H A flask was charged with (R)-3-(2,2-dimethyl-1,3-dioxolan-4-yl)-N-(3-(2-methylpyridin-3-yloxy)-5-(pyridin-2-ylthio)pyridin-2-yl)-1,2,4-thiadiazol-5-amine (3.8 g, 7.683 mmol) and added ethanol (40 mL). 3M HCl (5.122 ml, 15.37 mmol) was added, and the reaction was heated to 70 °C for 1 hour, then cooled to ambient temperature. The ethanol removed in vacuo and saturated sodium bicarbonate solution was added. The aqueous layer was extracted with ethyl acetate.
• Step A To 600 mL of DMF in a 4 neck 3000 mL round bottom flask equipped with an overhead stir mechanism under nitrogen was added 2-methylpyridin-3-ol (71.8 g, 658 mmol) and the reaction was cooled to 2 °C. Sodium hydride (60%; 26.3 g, 658 mmol) was added over a period of 30 minutes at a rate such that the internal temperature did not exceed 10 °C. The reaction was stirred while warming to ambient temperature for 1 hour. 5-Bromo-3-nitropicolinonitrile (150 g, 658 mmol) in a solution of 400 mL of DMF was added in two portions and the reaction was held at ambient temperature for 1.5 hour.
• Step B To concentrated H 2 SO 4 (90 mL) cooled with an ice bath was added 3-(2-methylpyridin-3-yloxy)-5-(pyridin-2-ylthio)picolinonitrile (43 g, 130 mmol) in portions such that the internal temperature did not exceed 50 °C but did not go below 25 °C. After complete addition, the mixture was stirred in the ice bath until the reaction started to cool, at which point the reaction was removed from the ice bath and the mixture was heated to 50 °C. The reaction was cooled to ambient temperature and then added to ice water slowly over 3 minutes (about 1400 mL of 30% ice in water).
• the mixture was further cooled in an ice bath to 5 °C and neutralized to about pH 10 with 4M NaOH (about 800 mL) while maintaining the internal temperature below 20 °C, at which point a solid formed.
• the mixture was stirred for 20 minutes, then filtered and washed with MTBE (5 x 150 mL) and hexanes (5 x 100 mL), and dried at under vacuum to afford 3-(2-methylpyridin-3-yloxy)-5-(pyridin-2-ylthio)picolinamide (43 g, 96%).
• Step C To a 3-neck 2 L round bottom flask was added 2M aqueous sodium hydroxide (343 ml, 686 mmol) and the solution was cooled in an ice bath. Bromine (12 ml, 257 mmol) was added and the reaction was stirred for 30 minutes while the ice bath was removed. 3-(2-Methylpyridin-3-yloxy)-5-(pyridin-2-ylthio)picolinamide (58 g, 171 mmol) was added as a slurry in about 600 mL of dioxanes in 1 portion. After 30 minutes, concentrated HCl was added in 1 mL portions to adjust the mixture to about pH 1.
• 2M aqueous sodium hydroxide 343 ml, 686 mmol
• Step D O,N-dimethylhydroxylamine hydrochloride (74.6 g, 765 mmol) was dissolved in THF (1 L) and pyridine (123 ml, 1531 mmol) was added and stirred for 30 minutes. Methacryloyl chloride (37.4 ml, 383 mmol) was added slowly and stirred overnight. The solids were filtered and concentrated. The residue was partitioned between water and CH 2 Cl 2 , washed with water, dried over sodium sulfate, filtered and concentrated to afford N-methoxy-N-methylmethacrylamide (56.5 g, 335 mmol, 87.5 % yield).
• Step E A round bottom flask was charged with t-BuOH (850 mL), water (850 mL), Ad-Mix- ⁇ (230 g, 166 mmol) and methanesulfonamide (15.8 g, 166 mmol). The mixture was stirred at ambient temperature until both phases were clear (about 5 minutes) and then cooled to 0 °C, after which orange salts precipitated. N-methoxy-N-methylmethacrylamide (21.5 g, 166 mmol) was added and the heterogeneous slurry was stirred vigorously at 0 °C for 2 hours, warmed to ambient temperature and stirred for 24 hours.
• Step F (R)-2,3-dihydroxy-N-methoxy-N,2-dimethylpropanamide (32 g, 196 mmol) was dissolved in 2,2-dimethoxypropane (241 ml, 1961 mmol) and 4-methylbenzenesulfonic acid hydrate (3.73 g, 19.6 mmol) was added and stirred at ambient temperature overnight.
• Step G (R)-N-methoxy-N,2,2,4-tetramethyl-1,3-dioxolane-4-carboxamide (22.9 g, 113 mmol) was dissolved in THF (500 mL) and cooled to -78 °C. 1 M LAH (124 ml, 124 mmol) was added slowly through an addition funnel over about 30 minutes. The reaction was stirred for another 30 minutes, a saturated aqueous NH 4 Cl was added (125 mL) and the reaction was allowed to warm to ambient temperature.
• Step H (R)-2,2,4-Trimethyl-1,3-dioxolane-4-carbaldehyde (6.9 g, 48 mmol) was dissolved in 1:1 methanol water (100 mL), and hydroxylamine hydrochloride (3.3 g, 48 mmol) and Na 2 CO 3 (2.5 g, 24 mmol) were added. The reaction was stirred at ambient temperature overnight. The methanol was removed in vacuo and the remaining material was extracted with CH 2 Cl 2 , dried over sodium sulfate, filtered and concentrated to afford (S)-2,2,4-trimethyl-1,3-dioxolane-4-carbaldehyde oxime (5.7 g, 36 mmol, 75 % yield).
• Step I (S)-2,2,4-Trimethyl-1,3-dioxolane-4-carbaldehyde oxime (5.7 g, 36 mmol) was dissolved in DMF (120 mL) and 1-chloropyrrolidine-2,5-dione (4.8 g, 36 mmol) was added. The reaction was stirred at ambient temperature overnight, and then poured in water (600 mL) with stirring.
• Step J (R)-N-hydroxy-2,2,4-trimethyl-1,3-dioxolane-4-carbimidoyl chloride (6.4 g, 33.1 mmol) was dissolved in Et 2 O (150 mL) and methanesulfonyl chloride (2.21 ml, 28.4 mmol) was added. Triethylamine (3.96 ml, 28.4 mmol) was added dropwise and the reaction stirred at ambient temperature for 1 hour. The resulting solids were filtered and the filtrate was concentrated.
• Step K (R)-2,2,4-trimethyl-N-(methylsulfonyloxy)-1,3-dioxolane-4-carbimidoyl chloride (350 mg, 1.29 mmol) was dissolved in CH 3 CN (6 mL). NaNCS (104 mg, 1.29 mmol) and pyridine (260 ⁇ l, 3.22 mmol) were added and the reaction was heated to 45 °C for 45 minutes. 3-(2-Methylpyridin-3-yloxy)-5-(pyridin-2-ylthio)pyridin-2-amine (200 mg, 0.644 mmol) was added and the reaction was heated to 70 °C for 24 hours.
• Step L (S)-N-(3-(2-methylpyridin-3-yloxy)-5-(pyridin-2-ylthio)pyridin-2-yl)-3-(2,2,4-trimethyl-1,3-dioxolan-4-yl)-1,2,4-thiadiazol-5-amine (55 mg, 0.108 mmol) was dissolved in EtOH (3 mL). 1M HCl (0.3 mL) was added and the mixture was stirred at ambient temperature for 24 hours. Additional 1M HCl (0.3 mL) was added and the mixture was stirred overnight. The mixture was partitioned between saturated aqueous sodium bicarbonate and CH 2 Cl 2 , dried over sodium sulfate, filtered and concentrated.
• Step A To 600 mL of DMF in a 4 neck 3000 mL round bottom flask equipped with an overhead stir mechanism under nitrogen was added 2-methylpyridin-3-ol (71.8 g, 658 mmol) and the reaction was cooled to 2 °C. Sodium hydride (60%; 26.3 g, 658 mmol) was added over a period of 30 minutes at a rate such that the internal temperature did not exceed 10 °C. The reaction was stirred while warming to ambient temperature for 1 hour. 5-Bromo-3-nitropicolinonitrile (150 g, 658 mmol) in a solution of 400 mL of DMF was added in two portions and the reaction held at ambient temperature for 1.5 hour.
• Step B To concentrated H 2 SO 4 (90 mL) cooled with an ice bath was added 3-(2-methylpyridin-3-yloxy)-5-(pyridin-2-ylthio)picolinonitrile (43 g, 130 mmol) in portions such that the internal temperature did not exceed 50 °C but did not go below 25 °C. After complete addition, the mixture was stirred in the ice bath until the reaction started to cool, at which point the reaction was removed from the ice bath and the mixture was heated to 50 °C. The reaction was cooled to ambient temperature and added to ice water slowly over 3 minutes (about 1400 mL of 30% ice in water).
• the mixture was further cooled in an ice bath to 5 °C and neutralized to about pH 10 with 4M NaOH (about 800 mL) at a rate such that the internal temperature did not exceed 20 °C, at which point a solid formed.
• the mixture was stirred for 20 minutes, then filtered and washed with MTBE (5 x150 mL), hexanes (5 x 100 mL), and dried at under vacuum to afford 3-(2-methylpyridin-3-yloxy)-5-(pyridin-2-ylthio)picolinamide (43 g, 96%).
• Step C To a 3-neck 2 L round bottom flask was added 2M aqueous sodium hydroxide (343 ml, 686 mmol) and the solution was cooled in an ice bath. Bromine (12 ml, 257 mmol) was added and the reaction was stirred for 30 minutes while the ice bath was removed. 3-(2-Methylpyridin-3-yloxy)-5-(pyridin-2-ylthio)picolinamide (58 g, 171 mmol) was added as a slurry in about 600 mL of dioxanes in 1 portion. After 30 minutes, concentrated HCl was added in 1 mL portions to about pH 1.
• 2M aqueous sodium hydroxide 343 ml, 686 mmol
• the reaction was stirred for 15 minutes and 4N NaOH was added to the solution to pH -10.
• the aqueous mixture was extracted with EtOAc (3 x 750 mL), washed with water (2 x 250 mL) and brine (300 mL), dried over MgSO 4 , filtered and concentrated.
• the material was dried in vacuo at 50 °C at which point a red solid formed.
• the solid was triturated with CH 2 Cl 2 (about 40 mL of CH 2 Cl 2 to 5 g of material) and the solid filtered. The solid was washed with CH 2 Cl 2 and dried under vacuum at 50 °C.
• Step D O,N-dimethylhydroxylamine hydrochloride (74.6 g, 765 mmol) was dissolved in THF (1 L) and pyridine (123 ml, 1531 mmol) was added and stirred for 30 min. Methacryloyl chloride (37.4 ml, 383 mmol) was added slowly and stirred overnight. The solids were filtered and concentrated. The residue was partitioned between water and CH 2 Cl 2 , washed with water, dried over sodium sulfate, filtered and concentrated to afford N-methoxy-N-methylmethacrylamide (56.5 g, 335 mmol, 87.5 % yield).
• Step E A round bottom flask was charged with t BuOH (850 mL), water (850 mL), Ad-Mix- ⁇ (230 g, 166 mmol) and methanesulfonamide (15.8 g, 166 mmol). The mixture was stirred at ambient temperature until both phases were clear (about 5 minutes) and then cooled to 0 °C, after which orange salts precipitated. N-methoxy-N-methylmethacrylamide (21.5 g, 166 mmol) was added and the heterogeneous slurry was stirred vigorously at 0 °C for 2 hours and warmed to ambient temperature and stirred for 24 hours.
• Step F (S)-2,3-dihydroxy-N-methoxy-N,2-dimethylpropanamide (32 g, 196 mmol) was dissolved in 2,2-dimethoxypropane (241 ml, 1961 mmol, 4-methylbenzenesulfonic acid hydrate (3.73 g, 19.6 mmol) was added, and the reaction was stirred at ambient temperature overnight. The reaction was partitioned between CH 2 Cl 2 and saturated aqueous sodium bicarbonate, extracted with CH 2 Cl 2 , dried over sodium sulfate, filtered and concentrated.
• Step G (S)-N-methoxy-N,2,2,4-tetramethyl-1,3-dioxolane-4-carboxamide (23.1 g, 114 mmol) was dissolved in THF (600 mL) and cooled to -78 °C. DIBAL-H (1M in toluene, 125 ml, 125 mmol) was added slowly through an addition funnel over about 15 minutes. The reaction was stirred for an additional 30 minutes at -78 °C and then quenched with saturated aqueous NH 4 Cl. The mixture was partitioned between EtOAc and water. The two layers were filtered through a silica plug and separated. The organic layer was dried over sodium sulfate, filtered and concentrated to afford (S)-2,2,4-trimethyl-1,3-dioxolane-4-carbaldehyde (16.4 g, 114 mmol, 100 % yield).
• Step H (S)-2,2,4-trimethyl-1,3-dioxolane-4-carbaldehyde (5.8 g, 40 mmol) was dissolved in 1:1 methanol water (100 mL) and hydroxylamine hydrochloride (2.8 g, 40 mmol) and Na 2 CO 3 (2.1 g, 20 mmol). The reaction was stirred at ambient temperature overnight, then concentrated in vacuo. The aqueous layer was extracted with CH 2 Cl 2 , and the organic layer was dried over sodium sulfate, filtered and concentrated to afford (R)-2,2,4-trimethyl-1,3-dioxolane-4-carbaldehyde oxime (4.8 g, 30 mmol, 75 % yield).
• Step I (R)-2,2,4-Trimethyl-1,3-dioxolane-4-carbaldehyde oxime (4.8 g, 30 mmol) was dissolved in DMF (100 mL) and 1-chloropyrrolidine-2,5-dione (4.0 g, 30 mmol) was added. The reaction was stirred at ambient temperature overnight, then poured in water (600 mL) with of stirring. After 15 minutes the cloudy suspension was extracted with EtOAc and washed with water and brine.
• Step J (S)-N-hydroxy-2,2,4-trimethyl-1,3-dioxolane-4-carbimidoyl chloride (5.5 g, 28.4 mmol) was dissolved in Et 2 O (150 mL) and methanesulfonyl chloride (2.21 ml, 28.4 mmol) was added. Triethylamine (3.96 ml, 28.4 mmol) was added dropwise and the reaction was stirred at ambient temperature for 1 hour. The resulting solids were filtered and the filtrate concentrated.
• Step K (S)-2,2,4-Trimethyl-N-(methylsulfonyloxy)-1,3-dioxolane-4-carbimidoyl chloride (438 mg, 1.61 mmol) was dissolved in CH 3 CN (6 mL) and NaNCS (131 mg, 1.61 mmol) and pyridine (311 ⁇ L, 3.87 mmol) were added and the reaction was heated to 45 °C for 45 minutes. 3-(2-Methylpyridin-3-yloxy)-5-(pyridin-2-ylthio)pyridin-2-amine (200 mg, 0.644 mmol) was added and the reaction was heated to 70 °C for 24 hours.
• Step L (R)-N-(3-(2-methylpyridin-3-yloxy)-5-(pyridin-2-ylthio)pyridin-2-yl)-3-(2,2,4-trimethyl-1,3-dioxolan-4-yl)-1,2,4-thiadiazol-5-amine (65 mg, 0.128 mmol) was dissolved in EtOH (3 mL) and 1M HCl (0.3 mL) was added. The mixture was stirred at ambient temperature for 24 hours. Additional 1M HCl (0.3 mL) was added and the mixture was stirred overnight.

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• 2010
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